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* [RFC PATCH v2 0/7] Clean up x86_64 boot code
@ 2019-05-01 19:39 ` David Woodhouse
  0 siblings, 0 replies; 18+ messages in thread
From: David Woodhouse @ 2019-05-01 19:39 UTC (permalink / raw)
  To: xen-devel

Some cleanups for the boot path, originally inspired by an attempt to
avoid scribbling on arbitrarily-chosen low memory.

In the no-real-mode case we don't need to bounce through low memory at
all; we can run the 32-bit trampoline in-place in the Xen image.

The variables containing information which is optionally discovered by
the real-mode boot code can be put back in place in the Xen image and we
can dispense with the bootsym() pointer gymnastics in C code which
access them in low memory.

Next up is killing reloc(), which AFAICT only exists to ensure that
the various breadcrumbs left all over the place by the Multiboot
bootloader aren't scribbled on when we copy the 16-bit boot trampoline
into low memory. Except that it's copying it out of the way... into
the top of low memory. Suspect if I tell kexec to put a segment there,
it's going to fail quite horribly.

Which leaves me with no valid reason for reloc() to be running this
early, so I may well kill it with fire too. I just need to find a
safe location for the 16-bit boot code.

v2: Fix wake code. Thanks Andy for testing.

David Woodhouse (7):
  x86/wakeup: Stop using %fs for lidt/lgdt
  x86/boot: Remove gratuitous call back into low-memory code
  x86/boot: Only jump into low trampoline code for real-mode boot
  x86/boot: Split bootsym() into four types of relocations
  x86/boot: Rename trampoline_{start,end} to boot_trampoline_{start,end}
  x86/boot: Copy 16-bit boot variables back up to Xen image
  x86/boot: Do not use trampoline for no-real-mode boot paths

 xen/arch/x86/acpi/power.c         |   6 +-
 xen/arch/x86/boot/edd.S           |  18 ++--
 xen/arch/x86/boot/head.S          |  89 ++++++++++++------
 xen/arch/x86/boot/mem.S           |  35 +++-----
 xen/arch/x86/boot/trampoline.S    | 145 +++++++++++++++++++++++-------
 xen/arch/x86/boot/video.S         |  36 ++++----
 xen/arch/x86/boot/wakeup.S        |  23 ++---
 xen/arch/x86/cpu/common.c         |   2 +-
 xen/arch/x86/cpu/intel.c          |   2 +-
 xen/arch/x86/efi/efi-boot.h       |  31 +------
 xen/arch/x86/mm.c                 |   2 +-
 xen/arch/x86/platform_hypercall.c |  18 ++--
 xen/arch/x86/setup.c              |  72 ++++++++++++---
 xen/arch/x86/smpboot.c            |   6 +-
 xen/arch/x86/tboot.c              |   6 +-
 xen/arch/x86/x86_64/mm.c          |   2 +-
 xen/arch/x86/xen.lds.S            |  27 ++++--
 xen/include/asm-x86/acpi.h        |   2 +-
 xen/include/asm-x86/config.h      |  10 +--
 xen/include/asm-x86/e820.h        |   5 +-
 xen/include/asm-x86/edd.h         |   1 -
 21 files changed, 339 insertions(+), 199 deletions(-)

-- 
2.17.2


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^ permalink raw reply	[flat|nested] 18+ messages in thread

* [Xen-devel] [RFC PATCH v2 0/7] Clean up x86_64 boot code
@ 2019-05-01 19:39 ` David Woodhouse
  0 siblings, 0 replies; 18+ messages in thread
From: David Woodhouse @ 2019-05-01 19:39 UTC (permalink / raw)
  To: xen-devel

Some cleanups for the boot path, originally inspired by an attempt to
avoid scribbling on arbitrarily-chosen low memory.

In the no-real-mode case we don't need to bounce through low memory at
all; we can run the 32-bit trampoline in-place in the Xen image.

The variables containing information which is optionally discovered by
the real-mode boot code can be put back in place in the Xen image and we
can dispense with the bootsym() pointer gymnastics in C code which
access them in low memory.

Next up is killing reloc(), which AFAICT only exists to ensure that
the various breadcrumbs left all over the place by the Multiboot
bootloader aren't scribbled on when we copy the 16-bit boot trampoline
into low memory. Except that it's copying it out of the way... into
the top of low memory. Suspect if I tell kexec to put a segment there,
it's going to fail quite horribly.

Which leaves me with no valid reason for reloc() to be running this
early, so I may well kill it with fire too. I just need to find a
safe location for the 16-bit boot code.

v2: Fix wake code. Thanks Andy for testing.

David Woodhouse (7):
  x86/wakeup: Stop using %fs for lidt/lgdt
  x86/boot: Remove gratuitous call back into low-memory code
  x86/boot: Only jump into low trampoline code for real-mode boot
  x86/boot: Split bootsym() into four types of relocations
  x86/boot: Rename trampoline_{start,end} to boot_trampoline_{start,end}
  x86/boot: Copy 16-bit boot variables back up to Xen image
  x86/boot: Do not use trampoline for no-real-mode boot paths

 xen/arch/x86/acpi/power.c         |   6 +-
 xen/arch/x86/boot/edd.S           |  18 ++--
 xen/arch/x86/boot/head.S          |  89 ++++++++++++------
 xen/arch/x86/boot/mem.S           |  35 +++-----
 xen/arch/x86/boot/trampoline.S    | 145 +++++++++++++++++++++++-------
 xen/arch/x86/boot/video.S         |  36 ++++----
 xen/arch/x86/boot/wakeup.S        |  23 ++---
 xen/arch/x86/cpu/common.c         |   2 +-
 xen/arch/x86/cpu/intel.c          |   2 +-
 xen/arch/x86/efi/efi-boot.h       |  31 +------
 xen/arch/x86/mm.c                 |   2 +-
 xen/arch/x86/platform_hypercall.c |  18 ++--
 xen/arch/x86/setup.c              |  72 ++++++++++++---
 xen/arch/x86/smpboot.c            |   6 +-
 xen/arch/x86/tboot.c              |   6 +-
 xen/arch/x86/x86_64/mm.c          |   2 +-
 xen/arch/x86/xen.lds.S            |  27 ++++--
 xen/include/asm-x86/acpi.h        |   2 +-
 xen/include/asm-x86/config.h      |  10 +--
 xen/include/asm-x86/e820.h        |   5 +-
 xen/include/asm-x86/edd.h         |   1 -
 21 files changed, 339 insertions(+), 199 deletions(-)

-- 
2.17.2


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^ permalink raw reply	[flat|nested] 18+ messages in thread

* [RFC PATCH v2 1/7] x86/wakeup: Stop using %fs for lidt/lgdt
@ 2019-05-01 19:39   ` David Woodhouse
  0 siblings, 0 replies; 18+ messages in thread
From: David Woodhouse @ 2019-05-01 19:39 UTC (permalink / raw)
  To: xen-devel

From: David Woodhouse <dwmw@amazon.co.uk>

The wakeup code is now relocated alongside the trampoline code, so %ds
is just fine here.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
---
 xen/arch/x86/boot/wakeup.S | 11 ++---------
 1 file changed, 2 insertions(+), 9 deletions(-)

diff --git a/xen/arch/x86/boot/wakeup.S b/xen/arch/x86/boot/wakeup.S
index f9632eef95..8c52819171 100644
--- a/xen/arch/x86/boot/wakeup.S
+++ b/xen/arch/x86/boot/wakeup.S
@@ -40,11 +40,8 @@ ENTRY(wakeup_start)
         movw    %ax, %fs
         movw    $0x0e00 + 'L', %fs:(0x10)
 
-        # boot trampoline is under 1M, and shift its start into
-        # %fs to reference symbols in that area
-        mov     wakesym(trampoline_seg), %fs
-        lidt    %fs:bootsym(idt_48)
-        lgdt    %fs:bootsym(gdt_48)
+        lidt    bootsym(idt_48)
+        lgdt    bootsym(gdt_48)
 
         movw    $1, %ax
         lmsw    %ax             # Turn on CR0.PE 
@@ -102,10 +99,6 @@ GLOBAL(video_mode)
         .long 0
 GLOBAL(video_flags)
         .long 0
-trampoline_seg: .word 0
-        .pushsection .trampoline_seg, "a"
-        .long   trampoline_seg - .
-        .popsection
 
         .code32
 
-- 
2.17.2


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^ permalink raw reply related	[flat|nested] 18+ messages in thread

* [Xen-devel] [RFC PATCH v2 1/7] x86/wakeup: Stop using %fs for lidt/lgdt
@ 2019-05-01 19:39   ` David Woodhouse
  0 siblings, 0 replies; 18+ messages in thread
From: David Woodhouse @ 2019-05-01 19:39 UTC (permalink / raw)
  To: xen-devel

From: David Woodhouse <dwmw@amazon.co.uk>

The wakeup code is now relocated alongside the trampoline code, so %ds
is just fine here.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
---
 xen/arch/x86/boot/wakeup.S | 11 ++---------
 1 file changed, 2 insertions(+), 9 deletions(-)

diff --git a/xen/arch/x86/boot/wakeup.S b/xen/arch/x86/boot/wakeup.S
index f9632eef95..8c52819171 100644
--- a/xen/arch/x86/boot/wakeup.S
+++ b/xen/arch/x86/boot/wakeup.S
@@ -40,11 +40,8 @@ ENTRY(wakeup_start)
         movw    %ax, %fs
         movw    $0x0e00 + 'L', %fs:(0x10)
 
-        # boot trampoline is under 1M, and shift its start into
-        # %fs to reference symbols in that area
-        mov     wakesym(trampoline_seg), %fs
-        lidt    %fs:bootsym(idt_48)
-        lgdt    %fs:bootsym(gdt_48)
+        lidt    bootsym(idt_48)
+        lgdt    bootsym(gdt_48)
 
         movw    $1, %ax
         lmsw    %ax             # Turn on CR0.PE 
@@ -102,10 +99,6 @@ GLOBAL(video_mode)
         .long 0
 GLOBAL(video_flags)
         .long 0
-trampoline_seg: .word 0
-        .pushsection .trampoline_seg, "a"
-        .long   trampoline_seg - .
-        .popsection
 
         .code32
 
-- 
2.17.2


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^ permalink raw reply related	[flat|nested] 18+ messages in thread

* [RFC PATCH v2 2/7] x86/boot: Remove gratuitous call back into low-memory code
@ 2019-05-01 19:39   ` David Woodhouse
  0 siblings, 0 replies; 18+ messages in thread
From: David Woodhouse @ 2019-05-01 19:39 UTC (permalink / raw)
  To: xen-devel

From: David Woodhouse <dwmw@amazon.co.uk>

We appear to have implemented a memcpy() in the low-memory trampoline
which we then call into from __start_xen(), for no adequately defined
reason.

Kill it with fire.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
---
 xen/arch/x86/boot/mem.S    | 27 +++++----------------------
 xen/arch/x86/setup.c       | 12 ++++++++++++
 xen/include/asm-x86/e820.h |  5 ++---
 3 files changed, 19 insertions(+), 25 deletions(-)

diff --git a/xen/arch/x86/boot/mem.S b/xen/arch/x86/boot/mem.S
index c6a9bd4d3b..2d61d28835 100644
--- a/xen/arch/x86/boot/mem.S
+++ b/xen/arch/x86/boot/mem.S
@@ -7,7 +7,7 @@ get_memory_map:
 
 .Lmeme820:
         xorl    %ebx, %ebx                      # continuation counter
-        movw    $bootsym(e820map), %di             # point into the whitelist
+        movw    $bootsym(bios_e820map), %di     # point into the whitelist
                                                 # so we can have the bios
                                                 # directly write into it.
 
@@ -22,8 +22,8 @@ get_memory_map:
         cmpl    $SMAP,%eax                      # check the return is `SMAP'
         jne     .Lmem88
 
-        incw    bootsym(e820nr)
-        cmpw    $E820_BIOS_MAX,bootsym(e820nr)  # up to this many entries
+        incw    bootsym(bios_e820nr)
+        cmpw    $E820_BIOS_MAX,bootsym(bios_e820nr) # up to this many entries
         jae     .Lmem88
 
         movw    %di,%ax
@@ -66,27 +66,10 @@ get_memory_map:
 
         ret
 
-/*
- * Copy E820 map obtained from BIOS to a buffer allocated by Xen.
- * Input: %rdi: target address of e820 entry array
- *        %esi: maximum number of entries to copy
- * Output: %eax: number of entries copied
- */
-        .code64
-ENTRY(e820map_copy)
-        mov     %esi, %eax
-        lea     e820map(%rip), %rsi
-        mov     e820nr(%rip), %ecx
-        cmp     %ecx, %eax
-        cmova   %ecx, %eax                      # number of entries to move
-        imul    $5, %eax, %ecx
-        rep movsl                               # do the move
-        ret
-
         .align  4
-e820map:
+GLOBAL(bios_e820map)
         .fill   E820_BIOS_MAX*20,1,0
-e820nr:
+GLOBAL(bios_e820nr)
         .long   0
 GLOBAL(lowmem_kb)
         .long   0
diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c
index a353d76f9a..5fa7d3b79c 100644
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -664,6 +664,18 @@ static char * __init cmdline_cook(char *p, const char *loader_name)
     return p;
 }
 
+static int copy_bios_e820(struct e820entry *map, unsigned int limit)
+{
+    unsigned int n = bootsym(bios_e820nr);
+    if (n > limit)
+        n = limit;
+
+    if (n)
+        memcpy(map, bootsym(bios_e820map), sizeof(*map) * n);
+
+    return n;
+}
+
 void __init noreturn __start_xen(unsigned long mbi_p)
 {
     char *memmap_type = NULL;
diff --git a/xen/include/asm-x86/e820.h b/xen/include/asm-x86/e820.h
index ee317b17aa..52916fb75d 100644
--- a/xen/include/asm-x86/e820.h
+++ b/xen/include/asm-x86/e820.h
@@ -37,8 +37,7 @@ extern struct e820map e820_raw;
 
 /* These symbols live in the boot trampoline. */
 extern unsigned int lowmem_kb, highmem_kb;
-unsigned int e820map_copy(struct e820entry *map, unsigned int limit);
-
-#define copy_bios_e820 bootsym(e820map_copy)
+extern struct e820map bios_e820map[];
+extern unsigned int bios_e820nr;
 
 #endif /*__E820_HEADER*/
-- 
2.17.2


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^ permalink raw reply related	[flat|nested] 18+ messages in thread

* [Xen-devel] [RFC PATCH v2 2/7] x86/boot: Remove gratuitous call back into low-memory code
@ 2019-05-01 19:39   ` David Woodhouse
  0 siblings, 0 replies; 18+ messages in thread
From: David Woodhouse @ 2019-05-01 19:39 UTC (permalink / raw)
  To: xen-devel

From: David Woodhouse <dwmw@amazon.co.uk>

We appear to have implemented a memcpy() in the low-memory trampoline
which we then call into from __start_xen(), for no adequately defined
reason.

Kill it with fire.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
---
 xen/arch/x86/boot/mem.S    | 27 +++++----------------------
 xen/arch/x86/setup.c       | 12 ++++++++++++
 xen/include/asm-x86/e820.h |  5 ++---
 3 files changed, 19 insertions(+), 25 deletions(-)

diff --git a/xen/arch/x86/boot/mem.S b/xen/arch/x86/boot/mem.S
index c6a9bd4d3b..2d61d28835 100644
--- a/xen/arch/x86/boot/mem.S
+++ b/xen/arch/x86/boot/mem.S
@@ -7,7 +7,7 @@ get_memory_map:
 
 .Lmeme820:
         xorl    %ebx, %ebx                      # continuation counter
-        movw    $bootsym(e820map), %di             # point into the whitelist
+        movw    $bootsym(bios_e820map), %di     # point into the whitelist
                                                 # so we can have the bios
                                                 # directly write into it.
 
@@ -22,8 +22,8 @@ get_memory_map:
         cmpl    $SMAP,%eax                      # check the return is `SMAP'
         jne     .Lmem88
 
-        incw    bootsym(e820nr)
-        cmpw    $E820_BIOS_MAX,bootsym(e820nr)  # up to this many entries
+        incw    bootsym(bios_e820nr)
+        cmpw    $E820_BIOS_MAX,bootsym(bios_e820nr) # up to this many entries
         jae     .Lmem88
 
         movw    %di,%ax
@@ -66,27 +66,10 @@ get_memory_map:
 
         ret
 
-/*
- * Copy E820 map obtained from BIOS to a buffer allocated by Xen.
- * Input: %rdi: target address of e820 entry array
- *        %esi: maximum number of entries to copy
- * Output: %eax: number of entries copied
- */
-        .code64
-ENTRY(e820map_copy)
-        mov     %esi, %eax
-        lea     e820map(%rip), %rsi
-        mov     e820nr(%rip), %ecx
-        cmp     %ecx, %eax
-        cmova   %ecx, %eax                      # number of entries to move
-        imul    $5, %eax, %ecx
-        rep movsl                               # do the move
-        ret
-
         .align  4
-e820map:
+GLOBAL(bios_e820map)
         .fill   E820_BIOS_MAX*20,1,0
-e820nr:
+GLOBAL(bios_e820nr)
         .long   0
 GLOBAL(lowmem_kb)
         .long   0
diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c
index a353d76f9a..5fa7d3b79c 100644
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -664,6 +664,18 @@ static char * __init cmdline_cook(char *p, const char *loader_name)
     return p;
 }
 
+static int copy_bios_e820(struct e820entry *map, unsigned int limit)
+{
+    unsigned int n = bootsym(bios_e820nr);
+    if (n > limit)
+        n = limit;
+
+    if (n)
+        memcpy(map, bootsym(bios_e820map), sizeof(*map) * n);
+
+    return n;
+}
+
 void __init noreturn __start_xen(unsigned long mbi_p)
 {
     char *memmap_type = NULL;
diff --git a/xen/include/asm-x86/e820.h b/xen/include/asm-x86/e820.h
index ee317b17aa..52916fb75d 100644
--- a/xen/include/asm-x86/e820.h
+++ b/xen/include/asm-x86/e820.h
@@ -37,8 +37,7 @@ extern struct e820map e820_raw;
 
 /* These symbols live in the boot trampoline. */
 extern unsigned int lowmem_kb, highmem_kb;
-unsigned int e820map_copy(struct e820entry *map, unsigned int limit);
-
-#define copy_bios_e820 bootsym(e820map_copy)
+extern struct e820map bios_e820map[];
+extern unsigned int bios_e820nr;
 
 #endif /*__E820_HEADER*/
-- 
2.17.2


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^ permalink raw reply related	[flat|nested] 18+ messages in thread

* [RFC PATCH v2 3/7] x86/boot: Only jump into low trampoline code for real-mode boot
@ 2019-05-01 19:39   ` David Woodhouse
  0 siblings, 0 replies; 18+ messages in thread
From: David Woodhouse @ 2019-05-01 19:39 UTC (permalink / raw)
  To: xen-devel

From: David Woodhouse <dwmw@amazon.co.uk>

If the no-real-mode flag is set, don't go there at all. This is a prelude
to not even putting it there in the first place.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
---
 xen/arch/x86/boot/head.S       | 10 ++++++++++
 xen/arch/x86/boot/trampoline.S |  4 ----
 2 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/xen/arch/x86/boot/head.S b/xen/arch/x86/boot/head.S
index db19ac6fd8..7c30de3671 100644
--- a/xen/arch/x86/boot/head.S
+++ b/xen/arch/x86/boot/head.S
@@ -734,7 +734,17 @@ trampoline_setup:
         /* Switch to low-memory stack which lives at the end of trampoline region. */
         mov     sym_fs(trampoline_phys),%edi
         lea     TRAMPOLINE_SPACE+TRAMPOLINE_STACK_SPACE(%edi),%esp
+        cmpb    $0, sym_fs(skip_realmode)
+        jz      1f
+        /* If no-real-mode, jump straight to trampoline_protmode_entry */
+        lea     trampoline_protmode_entry-trampoline_start(%edi),%eax
+        /* EBX == 0 indicates we are the BP (Boot Processor). */
+        xor     %ebx,%ebx
+        jmp     2f
+1:
+        /* Go via 16-bit code in trampoline_boot_cpu_entry */
         lea     trampoline_boot_cpu_entry-trampoline_start(%edi),%eax
+2:
         pushl   $BOOT_CS32
         push    %eax
 
diff --git a/xen/arch/x86/boot/trampoline.S b/xen/arch/x86/boot/trampoline.S
index 5588c7986a..df0ffd5013 100644
--- a/xen/arch/x86/boot/trampoline.S
+++ b/xen/arch/x86/boot/trampoline.S
@@ -187,9 +187,6 @@ start64:
 
         .code32
 trampoline_boot_cpu_entry:
-        cmpb    $0,bootsym_rel(skip_realmode,5)
-        jnz     .Lskip_realmode
-
         /* Load pseudo-real-mode segments. */
         mov     $BOOT_PSEUDORM_DS,%eax
         mov     %eax,%ds
@@ -269,7 +266,6 @@ trampoline_boot_cpu_entry:
         mov     %eax,%gs
         mov     %eax,%ss
 
-.Lskip_realmode:
         /* EBX == 0 indicates we are the BP (Boot Processor). */
         xor     %ebx,%ebx
 
-- 
2.17.2


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^ permalink raw reply related	[flat|nested] 18+ messages in thread

* [Xen-devel] [RFC PATCH v2 3/7] x86/boot: Only jump into low trampoline code for real-mode boot
@ 2019-05-01 19:39   ` David Woodhouse
  0 siblings, 0 replies; 18+ messages in thread
From: David Woodhouse @ 2019-05-01 19:39 UTC (permalink / raw)
  To: xen-devel

From: David Woodhouse <dwmw@amazon.co.uk>

If the no-real-mode flag is set, don't go there at all. This is a prelude
to not even putting it there in the first place.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
---
 xen/arch/x86/boot/head.S       | 10 ++++++++++
 xen/arch/x86/boot/trampoline.S |  4 ----
 2 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/xen/arch/x86/boot/head.S b/xen/arch/x86/boot/head.S
index db19ac6fd8..7c30de3671 100644
--- a/xen/arch/x86/boot/head.S
+++ b/xen/arch/x86/boot/head.S
@@ -734,7 +734,17 @@ trampoline_setup:
         /* Switch to low-memory stack which lives at the end of trampoline region. */
         mov     sym_fs(trampoline_phys),%edi
         lea     TRAMPOLINE_SPACE+TRAMPOLINE_STACK_SPACE(%edi),%esp
+        cmpb    $0, sym_fs(skip_realmode)
+        jz      1f
+        /* If no-real-mode, jump straight to trampoline_protmode_entry */
+        lea     trampoline_protmode_entry-trampoline_start(%edi),%eax
+        /* EBX == 0 indicates we are the BP (Boot Processor). */
+        xor     %ebx,%ebx
+        jmp     2f
+1:
+        /* Go via 16-bit code in trampoline_boot_cpu_entry */
         lea     trampoline_boot_cpu_entry-trampoline_start(%edi),%eax
+2:
         pushl   $BOOT_CS32
         push    %eax
 
diff --git a/xen/arch/x86/boot/trampoline.S b/xen/arch/x86/boot/trampoline.S
index 5588c7986a..df0ffd5013 100644
--- a/xen/arch/x86/boot/trampoline.S
+++ b/xen/arch/x86/boot/trampoline.S
@@ -187,9 +187,6 @@ start64:
 
         .code32
 trampoline_boot_cpu_entry:
-        cmpb    $0,bootsym_rel(skip_realmode,5)
-        jnz     .Lskip_realmode
-
         /* Load pseudo-real-mode segments. */
         mov     $BOOT_PSEUDORM_DS,%eax
         mov     %eax,%ds
@@ -269,7 +266,6 @@ trampoline_boot_cpu_entry:
         mov     %eax,%gs
         mov     %eax,%ss
 
-.Lskip_realmode:
         /* EBX == 0 indicates we are the BP (Boot Processor). */
         xor     %ebx,%ebx
 
-- 
2.17.2


_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xenproject.org
https://lists.xenproject.org/mailman/listinfo/xen-devel

^ permalink raw reply related	[flat|nested] 18+ messages in thread

* [RFC PATCH v2 4/7] x86/boot: Split bootsym() into four types of relocations
@ 2019-05-01 19:39   ` David Woodhouse
  0 siblings, 0 replies; 18+ messages in thread
From: David Woodhouse @ 2019-05-01 19:39 UTC (permalink / raw)
  To: xen-devel

From: David Woodhouse <dwmw@amazon.co.uk>

As a first step toward using the low-memory trampoline only when necessary
for a legacy boot without no-real-mode, clean up the relocations into
three separate groups.

 • bootsym() is now used only at boot time when no-real-mode isn't set.

 • bootdatasym() is for variables containing information discovered by
   the 16-bit boot code. This is currently accessed directly in place
   in low memory by Xen at runtime, but will be copied back to its
   location in high memory to avoid the pointer gymnastics (and because
   a subsequent patch will stop copying the 16-bit boot code into low
   memory at all when it isn't being used).

 • trampsym() is for the permanent 16-bit trampoline used for AP startup
   and for wake from sleep. This is not used at boot, and can be copied
   into (properly allocated) low memory once the system is running.

 • tramp32sym() is used both at boot and for AP startup/wakeup. During
   boot it can be used in-place, running from the physical address of
   the Xen image. For AP startup it can't, because at that point there
   isn't a full 1:1 mapping of all memory; only the low trampoline page
   is mapped.

No (intentional) functional change yet; just a "cleanup" to allow the
various parts to be treated separately in subsequent patches.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
---
 xen/arch/x86/boot/edd.S        | 16 +++----
 xen/arch/x86/boot/head.S       | 22 +++++++--
 xen/arch/x86/boot/mem.S        | 12 ++---
 xen/arch/x86/boot/trampoline.S | 86 ++++++++++++++++++++++++++--------
 xen/arch/x86/boot/video.S      |  6 +--
 xen/arch/x86/boot/wakeup.S     | 16 +++----
 xen/arch/x86/efi/efi-boot.h    |  8 ++--
 xen/arch/x86/xen.lds.S         | 15 ++++--
 8 files changed, 125 insertions(+), 56 deletions(-)

diff --git a/xen/arch/x86/boot/edd.S b/xen/arch/x86/boot/edd.S
index 3df712bce1..434bbbd960 100644
--- a/xen/arch/x86/boot/edd.S
+++ b/xen/arch/x86/boot/edd.S
@@ -41,7 +41,7 @@ get_edd:
 # This code is sensitive to the size of the structs in edd.h
 edd_start:
         /* ds:si points at fn48 results. Fn41 results go immediately before. */
-        movw    $bootsym(boot_edd_info)+EDDEXTSIZE, %si
+        movw    $bootdatasym(boot_edd_info)+EDDEXTSIZE, %si
         movb    $0x80, %dl                      # BIOS device 0x80
 
 edd_check_ext:
@@ -56,7 +56,7 @@ edd_check_ext:
         movb    %dl, %ds:-8(%si)                # store device number
         movb    %ah, %ds:-7(%si)                # store version
         movw    %cx, %ds:-6(%si)                # store extensions
-        incb    bootsym(boot_edd_info_nr)       # note that we stored something
+        incb    bootdatasym(boot_edd_info_nr)   # note that we stored something
 
 edd_get_device_params:
         movw    $EDDPARMSIZE, %ds:(%si)         # put size
@@ -97,7 +97,7 @@ edd_legacy_done:
 edd_next:
         incb    %dl                             # increment to next device
         jz      edd_done
-        cmpb    $EDD_INFO_MAX,bootsym(boot_edd_info_nr)
+        cmpb    $EDD_INFO_MAX,bootdatasym(boot_edd_info_nr)
         jb      edd_check_ext
 
 edd_done:
@@ -108,11 +108,11 @@ edd_done:
 .Ledd_mbr_sig_start:
         pushw   %es
         movb    $0x80, %dl                      # from device 80
-        movw    $bootsym(boot_mbr_signature), %bx # store buffer ptr in bx
+        movw    $bootdatasym(boot_mbr_signature), %bx # store buffer ptr in bx
 .Ledd_mbr_sig_read:
         pushw   %bx
-        movw    $bootsym(boot_edd_info), %bx
-        movzbw  bootsym(boot_edd_info_nr), %cx
+        movw    $bootdatasym(boot_edd_info), %bx
+        movzbw  bootdatasym(boot_edd_info_nr), %cx
         jcxz    .Ledd_mbr_sig_default
 .Ledd_mbr_sig_find_info:
         cmpb    %dl, (%bx)
@@ -151,12 +151,12 @@ edd_done:
         jne     .Ledd_mbr_sig_next
         movb    %dl, (%bx)                      # store BIOS drive number
         movl    %ecx, 4(%bx)                    # store signature from MBR
-        incb    bootsym(boot_mbr_signature_nr)  # note that we stored something
+        incb    bootdatasym(boot_mbr_signature_nr) # note that we stored something
         addw    $8, %bx                         # increment sig buffer ptr
 .Ledd_mbr_sig_next:
         incb    %dl                             # increment to next device
         jz      .Ledd_mbr_sig_done
-        cmpb    $EDD_MBR_SIG_MAX, bootsym(boot_mbr_signature_nr)
+        cmpb    $EDD_MBR_SIG_MAX, bootdatasym(boot_mbr_signature_nr)
         jb      .Ledd_mbr_sig_read
 .Ledd_mbr_sig_done:
         popw    %es
diff --git a/xen/arch/x86/boot/head.S b/xen/arch/x86/boot/head.S
index 7c30de3671..5b4f211a9b 100644
--- a/xen/arch/x86/boot/head.S
+++ b/xen/arch/x86/boot/head.S
@@ -706,14 +706,30 @@ trampoline_setup:
         cmp     $sym_offs(__trampoline_rel_stop),%edi
         jb      1b
 
-        /* Patch in the trampoline segment. */
+        mov     $sym_offs(__trampoline32_rel_start),%edi
+1:
+        mov     %fs:(%edi),%eax
+        add     %edx,%fs:(%edi,%eax)
+        add     $4,%edi
+        cmp     $sym_offs(__trampoline32_rel_stop),%edi
+        jb      1b
+
+        mov     $sym_offs(__bootsym_rel_start),%edi
+1:
+        mov     %fs:(%edi),%eax
+        add     %edx,%fs:(%edi,%eax)
+        add     $4,%edi
+        cmp     $sym_offs(__bootsym_rel_stop),%edi
+        jb      1b
+
+        /* Patch in the boot trampoline segment. */
         shr     $4,%edx
-        mov     $sym_offs(__trampoline_seg_start),%edi
+        mov     $sym_offs(__bootsym_seg_start),%edi
 1:
         mov     %fs:(%edi),%eax
         mov     %dx,%fs:(%edi,%eax)
         add     $4,%edi
-        cmp     $sym_offs(__trampoline_seg_stop),%edi
+        cmp     $sym_offs(__bootsym_seg_stop),%edi
         jb      1b
 
         /* Do not parse command line on EFI platform here. */
diff --git a/xen/arch/x86/boot/mem.S b/xen/arch/x86/boot/mem.S
index 2d61d28835..aa39608442 100644
--- a/xen/arch/x86/boot/mem.S
+++ b/xen/arch/x86/boot/mem.S
@@ -7,7 +7,7 @@ get_memory_map:
 
 .Lmeme820:
         xorl    %ebx, %ebx                      # continuation counter
-        movw    $bootsym(bios_e820map), %di     # point into the whitelist
+        movw    $bootdatasym(bios_e820map), %di # point into the whitelist
                                                 # so we can have the bios
                                                 # directly write into it.
 
@@ -22,8 +22,8 @@ get_memory_map:
         cmpl    $SMAP,%eax                      # check the return is `SMAP'
         jne     .Lmem88
 
-        incw    bootsym(bios_e820nr)
-        cmpw    $E820_BIOS_MAX,bootsym(bios_e820nr) # up to this many entries
+        incw    bootdatasym(bios_e820nr)
+        cmpw    $E820_BIOS_MAX,bootdatasym(bios_e820nr) # up to this many entries
         jae     .Lmem88
 
         movw    %di,%ax
@@ -35,7 +35,7 @@ get_memory_map:
 .Lmem88:
         movb    $0x88, %ah
         int     $0x15
-        movw    %ax,bootsym(highmem_kb)
+        movw    %ax,bootdatasym(highmem_kb)
 
 .Lmeme801:
         stc                                     # fix to work around buggy
@@ -58,11 +58,11 @@ get_memory_map:
         shll    $6,%edx                         # and go from 64k to 1k chunks
         movzwl  %cx, %ecx
         addl    %ecx, %edx                      # add in lower memory
-        movl    %edx,bootsym(highmem_kb)        # store extended memory size
+        movl    %edx,bootdatasym(highmem_kb)    # store extended memory size
 
 .Lint12:
         int     $0x12
-        movw    %ax,bootsym(lowmem_kb)
+        movw    %ax,bootdatasym(lowmem_kb)
 
         ret
 
diff --git a/xen/arch/x86/boot/trampoline.S b/xen/arch/x86/boot/trampoline.S
index df0ffd5013..e77b4bea36 100644
--- a/xen/arch/x86/boot/trampoline.S
+++ b/xen/arch/x86/boot/trampoline.S
@@ -16,21 +16,62 @@
  * not guaranteed to persist.
  */
 
-/* NB. bootsym() is only usable in real mode, or via BOOT_PSEUDORM_DS. */
+/*
+ * There are four sets of relocations:
+ *
+ * bootsym():     Boot-time code relocated to low memory and run only once.
+ *                Only usable at boot, in real mode or via BOOT_PSEUDORM_DS.
+ * bootdatasym(): Boot-time BIOS-discovered data, relocated back up to Xen
+ *                image after discovery.
+ * trampsym():    Trampoline code relocated into low memory for AP startup
+ *                and wakeup.
+ * tramp32sym():  32-bit trampoline code which at boot can be used directly
+ *                from the Xen image in memory, but which will need to be
+ *                relocated into low (well, into *mapped*) memory in order
+ *                to be used for AP startup.
+ */
 #undef bootsym
 #define bootsym(s) ((s)-trampoline_start)
 
 #define bootsym_rel(sym, off, opnd...)     \
         bootsym(sym),##opnd;               \
 111:;                                      \
-        .pushsection .trampoline_rel, "a"; \
+        .pushsection .bootsym_rel, "a";    \
         .long 111b - (off) - .;            \
         .popsection
 
 #define bootsym_segrel(sym, off)           \
         $0,$bootsym(sym);                  \
 111:;                                      \
-        .pushsection .trampoline_seg, "a"; \
+        .pushsection .bootsym_seg, "a";    \
+        .long 111b - (off) - .;            \
+        .popsection
+
+#define bootdatasym(s) ((s)-trampoline_start)
+#define bootdatasym_rel(sym, off, opnd...) \
+        bootdatasym(sym),##opnd;           \
+111:;                                      \
+        .pushsection .bootdatasym_rel, "a";\
+        .long 111b - (off) - .;            \
+        .popsection
+
+#undef trampsym
+#define trampsym(s) ((s)-trampoline_start)
+
+#define trampsym_rel(sym, off, opnd...)    \
+        trampsym(sym),##opnd;              \
+111:;                                      \
+        .pushsection .trampsym_rel, "a";   \
+        .long 111b - (off) - .;            \
+        .popsection
+
+#undef tramp32sym
+#define tramp32sym(s) ((s)-trampoline_start)
+
+#define tramp32sym_rel(sym, off, opnd...)  \
+        tramp32sym(sym),##opnd;            \
+111:;                                      \
+        .pushsection .tramp32sym_rel, "a"; \
         .long 111b - (off) - .;            \
         .popsection
 
@@ -41,24 +82,28 @@
 GLOBAL(trampoline_realmode_entry)
         mov     %cs,%ax
         mov     %ax,%ds
-        movb    $0xA5,bootsym(trampoline_cpu_started)
+        movb    $0xA5,trampsym(trampoline_cpu_started)
         cld
         cli
-        lidt    bootsym(idt_48)
-        lgdt    bootsym(gdt_48)
+        lidt    trampsym(idt_48)
+        lgdt    trampsym(gdt_48)
         mov     $1,%bl                    # EBX != 0 indicates we are an AP
         xor     %ax, %ax
         inc     %ax
         lmsw    %ax                       # CR0.PE = 1 (enter protected mode)
-        ljmpl   $BOOT_CS32,$bootsym_rel(trampoline_protmode_entry,6)
+        ljmpl   $BOOT_CS32,$tramp32sym_rel(trampoline_protmode_entry,6)
+
+GLOBAL(trampoline_cpu_started)
+        .byte   0
 
         .balign 8
         .word   0
 idt_48: .word   0, 0, 0 # base = limit = 0
         .word   0
 gdt_48: .word   6*8-1
-        .long   bootsym_rel(trampoline_gdt,4)
+        .long   tramp32sym_rel(trampoline_gdt,4)
 
+/* Start of tramp32sym section which can be used in place during boot */
 trampoline_gdt:
         /* 0x0000: unused */
         .quad   0x0000000000000000
@@ -79,8 +124,12 @@ trampoline_gdt:
          * address is computed at runtime.
          */
         .quad   0x00c0920000000fff
-
-        .pushsection .trampoline_rel, "a"
+        /*
+         * BOOT_PSEUDORM_CS and BOOT_PSEUDORM_DS are usable only at boot time,
+         * and their base addresses must reference the low location to which
+         * the boot-time code was loaded. Hence bootsym.
+         */
+        .pushsection .bootsym_rel, "a"
         .long   trampoline_gdt + BOOT_PSEUDORM_CS + 2 - .
         .long   trampoline_gdt + BOOT_PSEUDORM_DS + 2 - .
         .popsection
@@ -94,9 +143,6 @@ GLOBAL(cpuid_ext_features)
 GLOBAL(trampoline_xen_phys_start)
         .long   0
 
-GLOBAL(trampoline_cpu_started)
-        .byte   0
-
         .code32
 trampoline_protmode_entry:
         /* Set up a few descriptors: on entry only CS is guaranteed good. */
@@ -113,12 +159,12 @@ trampoline_protmode_entry:
 
         /* Load pagetable base register. */
         mov     $sym_offs(idle_pg_table),%eax
-        add     bootsym_rel(trampoline_xen_phys_start,4,%eax)
+        add     tramp32sym_rel(trampoline_xen_phys_start,4,%eax)
         mov     %eax,%cr3
 
         /* Adjust IA32_MISC_ENABLE if needed (for NX enabling below). */
-        mov     bootsym_rel(trampoline_misc_enable_off,4,%esi)
-        mov     bootsym_rel(trampoline_misc_enable_off+4,4,%edi)
+        mov     tramp32sym_rel(trampoline_misc_enable_off,4,%esi)
+        mov     tramp32sym_rel(trampoline_misc_enable_off+4,4,%edi)
         mov     %esi,%eax
         or      %edi,%eax
         jz      1f
@@ -132,7 +178,7 @@ trampoline_protmode_entry:
 1:
 
         /* Set up EFER (Extended Feature Enable Register). */
-        mov     bootsym_rel(cpuid_ext_features,4,%edi)
+        mov     tramp32sym_rel(cpuid_ext_features,4,%edi)
         movl    $MSR_EFER,%ecx
         rdmsr
         or      $EFER_LME|EFER_SCE,%eax   /* Long Mode + SYSCALL/SYSRET */
@@ -148,7 +194,7 @@ trampoline_protmode_entry:
 1:
 
         /* Now in compatibility mode. Long-jump into 64-bit mode. */
-        ljmp    $BOOT_CS64,$bootsym_rel(start64,6)
+        ljmp    $BOOT_CS64,$tramp32sym_rel(start64,6)
 
         .code64
 start64:
@@ -242,7 +288,7 @@ trampoline_boot_cpu_entry:
 
         mov     $0x0200,%ax
         int     $0x16
-        mov     %al,bootsym(kbd_shift_flags)
+        mov     %al,bootdatasym(kbd_shift_flags)
 
         /* Disable irqs before returning to protected mode. */
         cli
@@ -287,7 +333,7 @@ opt_edid:
         .byte   0
 
 #ifdef CONFIG_VIDEO
-GLOBAL(boot_vid_mode)
+boot_vid_mode:
         .word   VIDEO_80x25                     /* If we don't run at all, assume basic video mode 3 at 80x25. */
 vesa_size:
         .word   0,0,0                           /* width x depth x height */
diff --git a/xen/arch/x86/boot/video.S b/xen/arch/x86/boot/video.S
index 335a51c9b5..03907e9e9a 100644
--- a/xen/arch/x86/boot/video.S
+++ b/xen/arch/x86/boot/video.S
@@ -45,7 +45,7 @@
 #define PARAM_VESAPM_SEG        0x24
 #define PARAM_VESAPM_OFF        0x26
 #define PARAM_VESA_ATTRIB       0x28
-#define _param(param) bootsym(boot_vid_info)+(param)
+#define _param(param) bootdatasym(boot_vid_info)+(param)
 
 video:  xorw    %ax, %ax
         movw    %ax, %gs        # GS is zero
@@ -917,7 +917,7 @@ store_edid:
         cmpw    $0x004f, %ax            # Call failed?
         jne     .Lno_edid
 
-        movw    %bx, bootsym(boot_edid_caps)
+        movw    %bx, bootdatasym(boot_edid_caps)
 
         cmpb    $2, bootsym(opt_edid)   # EDID forced on cmdline (edid=force)?
         je      .Lforce_edid
@@ -933,7 +933,7 @@ store_edid:
         movw    $0x01, %bx
         movw    $0x00, %cx
         movw    $0x00, %dx
-        movw    $bootsym(boot_edid_info), %di
+        movw    $bootdatasym(boot_edid_info), %di
         int     $0x10
 
 .Lno_edid:
diff --git a/xen/arch/x86/boot/wakeup.S b/xen/arch/x86/boot/wakeup.S
index 8c52819171..1c58e2affb 100644
--- a/xen/arch/x86/boot/wakeup.S
+++ b/xen/arch/x86/boot/wakeup.S
@@ -40,12 +40,12 @@ ENTRY(wakeup_start)
         movw    %ax, %fs
         movw    $0x0e00 + 'L', %fs:(0x10)
 
-        lidt    bootsym(idt_48)
-        lgdt    bootsym(gdt_48)
+        lidt    trampsym(idt_48)
+        lgdt    trampsym(gdt_48)
 
         movw    $1, %ax
         lmsw    %ax             # Turn on CR0.PE 
-        ljmpl   $BOOT_CS32, $bootsym_rel(wakeup_32, 6)
+        ljmpl   $BOOT_CS32, $trampsym_rel(wakeup_32, 6)
 
 /* This code uses an extended set of video mode numbers. These include:
  * Aliases for standard modes
@@ -110,11 +110,11 @@ wakeup_32:
         mov     $BOOT_DS, %eax
         mov     %eax, %ds
         mov     %eax, %ss
-        mov     $bootsym_rel(wakeup_stack, 4, %esp)
+        mov     $trampsym_rel(wakeup_stack, 4, %esp)
 
         # check saved magic again
         mov     $sym_offs(saved_magic),%eax
-        add     bootsym_rel(trampoline_xen_phys_start, 4, %eax)
+        add     trampsym_rel(trampoline_xen_phys_start, 4, %eax)
         mov     (%eax), %eax
         cmp     $0x9abcdef0, %eax
         jne     bogus_saved_magic
@@ -127,12 +127,12 @@ wakeup_32:
 
         /* Load pagetable base register */
         mov     $sym_offs(idle_pg_table),%eax
-        add     bootsym_rel(trampoline_xen_phys_start,4,%eax)
+        add     trampsym_rel(trampoline_xen_phys_start,4,%eax)
         mov     %eax,%cr3
 
         /* Will cpuid feature change after resume? */
         /* Set up EFER (Extended Feature Enable Register). */
-        mov     bootsym_rel(cpuid_ext_features,4,%edi)
+        mov     trampsym_rel(cpuid_ext_features,4,%edi)
         test    $0x20100800,%edi /* SYSCALL/SYSRET, No Execute, Long Mode? */
         jz      .Lskip_eferw
         movl    $MSR_EFER,%ecx
@@ -154,7 +154,7 @@ wakeup_32:
 1:
 
         /* Now in compatibility mode. Long-jump to 64-bit mode */
-        ljmp    $BOOT_CS64, $bootsym_rel(wakeup_64,6)
+        ljmp    $BOOT_CS64, $trampsym_rel(wakeup_64,6)
 
         .code64
 wakeup_64:
diff --git a/xen/arch/x86/efi/efi-boot.h b/xen/arch/x86/efi/efi-boot.h
index 5789d2cb70..abc7d3e3b7 100644
--- a/xen/arch/x86/efi/efi-boot.h
+++ b/xen/arch/x86/efi/efi-boot.h
@@ -99,7 +99,7 @@ static void __init efi_arch_relocate_image(unsigned long delta)
 }
 
 extern const s32 __trampoline_rel_start[], __trampoline_rel_stop[];
-extern const s32 __trampoline_seg_start[], __trampoline_seg_stop[];
+extern const s32 __trampoline32_rel_start[], __trampoline32_rel_stop[];
 
 static void __init relocate_trampoline(unsigned long phys)
 {
@@ -115,10 +115,10 @@ static void __init relocate_trampoline(unsigned long phys)
           trampoline_ptr < __trampoline_rel_stop;
           ++trampoline_ptr )
         *(u32 *)(*trampoline_ptr + (long)trampoline_ptr) += phys;
-    for ( trampoline_ptr = __trampoline_seg_start;
-          trampoline_ptr < __trampoline_seg_stop;
+    for ( trampoline_ptr = __trampoline32_rel_start;
+          trampoline_ptr < __trampoline32_rel_stop;
           ++trampoline_ptr )
-        *(u16 *)(*trampoline_ptr + (long)trampoline_ptr) = phys >> 4;
+        *(u32 *)(*trampoline_ptr + (long)trampoline_ptr) += phys;
 }
 
 static void __init place_string(u32 *addr, const char *s)
diff --git a/xen/arch/x86/xen.lds.S b/xen/arch/x86/xen.lds.S
index a76e2ec8ef..54ac0c0993 100644
--- a/xen/arch/x86/xen.lds.S
+++ b/xen/arch/x86/xen.lds.S
@@ -221,11 +221,18 @@ SECTIONS
        *(.init.data.rel.*)
        . = ALIGN(4);
        __trampoline_rel_start = .;
-       *(.trampoline_rel)
+       *(.trampsym_rel)
        __trampoline_rel_stop = .;
-       __trampoline_seg_start = .;
-       *(.trampoline_seg)
-       __trampoline_seg_stop = .;
+       __trampoline32_rel_start = .;
+       *(.tramp32sym_rel)
+       __trampoline32_rel_stop = .;
+       __bootsym_rel_start = .;
+       *(.bootsym_rel)
+       *(.bootdatasym_rel)
+       __bootsym_rel_stop = .;
+       __bootsym_seg_start = .;
+       *(.bootsym_seg)
+       __bootsym_seg_stop = .;
        /*
         * struct alt_inst entries. From the header (alternative.h):
         * "Alternative instructions for different CPU types or capabilities"
-- 
2.17.2


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^ permalink raw reply related	[flat|nested] 18+ messages in thread

* [Xen-devel] [RFC PATCH v2 4/7] x86/boot: Split bootsym() into four types of relocations
@ 2019-05-01 19:39   ` David Woodhouse
  0 siblings, 0 replies; 18+ messages in thread
From: David Woodhouse @ 2019-05-01 19:39 UTC (permalink / raw)
  To: xen-devel

From: David Woodhouse <dwmw@amazon.co.uk>

As a first step toward using the low-memory trampoline only when necessary
for a legacy boot without no-real-mode, clean up the relocations into
three separate groups.

 • bootsym() is now used only at boot time when no-real-mode isn't set.

 • bootdatasym() is for variables containing information discovered by
   the 16-bit boot code. This is currently accessed directly in place
   in low memory by Xen at runtime, but will be copied back to its
   location in high memory to avoid the pointer gymnastics (and because
   a subsequent patch will stop copying the 16-bit boot code into low
   memory at all when it isn't being used).

 • trampsym() is for the permanent 16-bit trampoline used for AP startup
   and for wake from sleep. This is not used at boot, and can be copied
   into (properly allocated) low memory once the system is running.

 • tramp32sym() is used both at boot and for AP startup/wakeup. During
   boot it can be used in-place, running from the physical address of
   the Xen image. For AP startup it can't, because at that point there
   isn't a full 1:1 mapping of all memory; only the low trampoline page
   is mapped.

No (intentional) functional change yet; just a "cleanup" to allow the
various parts to be treated separately in subsequent patches.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
---
 xen/arch/x86/boot/edd.S        | 16 +++----
 xen/arch/x86/boot/head.S       | 22 +++++++--
 xen/arch/x86/boot/mem.S        | 12 ++---
 xen/arch/x86/boot/trampoline.S | 86 ++++++++++++++++++++++++++--------
 xen/arch/x86/boot/video.S      |  6 +--
 xen/arch/x86/boot/wakeup.S     | 16 +++----
 xen/arch/x86/efi/efi-boot.h    |  8 ++--
 xen/arch/x86/xen.lds.S         | 15 ++++--
 8 files changed, 125 insertions(+), 56 deletions(-)

diff --git a/xen/arch/x86/boot/edd.S b/xen/arch/x86/boot/edd.S
index 3df712bce1..434bbbd960 100644
--- a/xen/arch/x86/boot/edd.S
+++ b/xen/arch/x86/boot/edd.S
@@ -41,7 +41,7 @@ get_edd:
 # This code is sensitive to the size of the structs in edd.h
 edd_start:
         /* ds:si points at fn48 results. Fn41 results go immediately before. */
-        movw    $bootsym(boot_edd_info)+EDDEXTSIZE, %si
+        movw    $bootdatasym(boot_edd_info)+EDDEXTSIZE, %si
         movb    $0x80, %dl                      # BIOS device 0x80
 
 edd_check_ext:
@@ -56,7 +56,7 @@ edd_check_ext:
         movb    %dl, %ds:-8(%si)                # store device number
         movb    %ah, %ds:-7(%si)                # store version
         movw    %cx, %ds:-6(%si)                # store extensions
-        incb    bootsym(boot_edd_info_nr)       # note that we stored something
+        incb    bootdatasym(boot_edd_info_nr)   # note that we stored something
 
 edd_get_device_params:
         movw    $EDDPARMSIZE, %ds:(%si)         # put size
@@ -97,7 +97,7 @@ edd_legacy_done:
 edd_next:
         incb    %dl                             # increment to next device
         jz      edd_done
-        cmpb    $EDD_INFO_MAX,bootsym(boot_edd_info_nr)
+        cmpb    $EDD_INFO_MAX,bootdatasym(boot_edd_info_nr)
         jb      edd_check_ext
 
 edd_done:
@@ -108,11 +108,11 @@ edd_done:
 .Ledd_mbr_sig_start:
         pushw   %es
         movb    $0x80, %dl                      # from device 80
-        movw    $bootsym(boot_mbr_signature), %bx # store buffer ptr in bx
+        movw    $bootdatasym(boot_mbr_signature), %bx # store buffer ptr in bx
 .Ledd_mbr_sig_read:
         pushw   %bx
-        movw    $bootsym(boot_edd_info), %bx
-        movzbw  bootsym(boot_edd_info_nr), %cx
+        movw    $bootdatasym(boot_edd_info), %bx
+        movzbw  bootdatasym(boot_edd_info_nr), %cx
         jcxz    .Ledd_mbr_sig_default
 .Ledd_mbr_sig_find_info:
         cmpb    %dl, (%bx)
@@ -151,12 +151,12 @@ edd_done:
         jne     .Ledd_mbr_sig_next
         movb    %dl, (%bx)                      # store BIOS drive number
         movl    %ecx, 4(%bx)                    # store signature from MBR
-        incb    bootsym(boot_mbr_signature_nr)  # note that we stored something
+        incb    bootdatasym(boot_mbr_signature_nr) # note that we stored something
         addw    $8, %bx                         # increment sig buffer ptr
 .Ledd_mbr_sig_next:
         incb    %dl                             # increment to next device
         jz      .Ledd_mbr_sig_done
-        cmpb    $EDD_MBR_SIG_MAX, bootsym(boot_mbr_signature_nr)
+        cmpb    $EDD_MBR_SIG_MAX, bootdatasym(boot_mbr_signature_nr)
         jb      .Ledd_mbr_sig_read
 .Ledd_mbr_sig_done:
         popw    %es
diff --git a/xen/arch/x86/boot/head.S b/xen/arch/x86/boot/head.S
index 7c30de3671..5b4f211a9b 100644
--- a/xen/arch/x86/boot/head.S
+++ b/xen/arch/x86/boot/head.S
@@ -706,14 +706,30 @@ trampoline_setup:
         cmp     $sym_offs(__trampoline_rel_stop),%edi
         jb      1b
 
-        /* Patch in the trampoline segment. */
+        mov     $sym_offs(__trampoline32_rel_start),%edi
+1:
+        mov     %fs:(%edi),%eax
+        add     %edx,%fs:(%edi,%eax)
+        add     $4,%edi
+        cmp     $sym_offs(__trampoline32_rel_stop),%edi
+        jb      1b
+
+        mov     $sym_offs(__bootsym_rel_start),%edi
+1:
+        mov     %fs:(%edi),%eax
+        add     %edx,%fs:(%edi,%eax)
+        add     $4,%edi
+        cmp     $sym_offs(__bootsym_rel_stop),%edi
+        jb      1b
+
+        /* Patch in the boot trampoline segment. */
         shr     $4,%edx
-        mov     $sym_offs(__trampoline_seg_start),%edi
+        mov     $sym_offs(__bootsym_seg_start),%edi
 1:
         mov     %fs:(%edi),%eax
         mov     %dx,%fs:(%edi,%eax)
         add     $4,%edi
-        cmp     $sym_offs(__trampoline_seg_stop),%edi
+        cmp     $sym_offs(__bootsym_seg_stop),%edi
         jb      1b
 
         /* Do not parse command line on EFI platform here. */
diff --git a/xen/arch/x86/boot/mem.S b/xen/arch/x86/boot/mem.S
index 2d61d28835..aa39608442 100644
--- a/xen/arch/x86/boot/mem.S
+++ b/xen/arch/x86/boot/mem.S
@@ -7,7 +7,7 @@ get_memory_map:
 
 .Lmeme820:
         xorl    %ebx, %ebx                      # continuation counter
-        movw    $bootsym(bios_e820map), %di     # point into the whitelist
+        movw    $bootdatasym(bios_e820map), %di # point into the whitelist
                                                 # so we can have the bios
                                                 # directly write into it.
 
@@ -22,8 +22,8 @@ get_memory_map:
         cmpl    $SMAP,%eax                      # check the return is `SMAP'
         jne     .Lmem88
 
-        incw    bootsym(bios_e820nr)
-        cmpw    $E820_BIOS_MAX,bootsym(bios_e820nr) # up to this many entries
+        incw    bootdatasym(bios_e820nr)
+        cmpw    $E820_BIOS_MAX,bootdatasym(bios_e820nr) # up to this many entries
         jae     .Lmem88
 
         movw    %di,%ax
@@ -35,7 +35,7 @@ get_memory_map:
 .Lmem88:
         movb    $0x88, %ah
         int     $0x15
-        movw    %ax,bootsym(highmem_kb)
+        movw    %ax,bootdatasym(highmem_kb)
 
 .Lmeme801:
         stc                                     # fix to work around buggy
@@ -58,11 +58,11 @@ get_memory_map:
         shll    $6,%edx                         # and go from 64k to 1k chunks
         movzwl  %cx, %ecx
         addl    %ecx, %edx                      # add in lower memory
-        movl    %edx,bootsym(highmem_kb)        # store extended memory size
+        movl    %edx,bootdatasym(highmem_kb)    # store extended memory size
 
 .Lint12:
         int     $0x12
-        movw    %ax,bootsym(lowmem_kb)
+        movw    %ax,bootdatasym(lowmem_kb)
 
         ret
 
diff --git a/xen/arch/x86/boot/trampoline.S b/xen/arch/x86/boot/trampoline.S
index df0ffd5013..e77b4bea36 100644
--- a/xen/arch/x86/boot/trampoline.S
+++ b/xen/arch/x86/boot/trampoline.S
@@ -16,21 +16,62 @@
  * not guaranteed to persist.
  */
 
-/* NB. bootsym() is only usable in real mode, or via BOOT_PSEUDORM_DS. */
+/*
+ * There are four sets of relocations:
+ *
+ * bootsym():     Boot-time code relocated to low memory and run only once.
+ *                Only usable at boot, in real mode or via BOOT_PSEUDORM_DS.
+ * bootdatasym(): Boot-time BIOS-discovered data, relocated back up to Xen
+ *                image after discovery.
+ * trampsym():    Trampoline code relocated into low memory for AP startup
+ *                and wakeup.
+ * tramp32sym():  32-bit trampoline code which at boot can be used directly
+ *                from the Xen image in memory, but which will need to be
+ *                relocated into low (well, into *mapped*) memory in order
+ *                to be used for AP startup.
+ */
 #undef bootsym
 #define bootsym(s) ((s)-trampoline_start)
 
 #define bootsym_rel(sym, off, opnd...)     \
         bootsym(sym),##opnd;               \
 111:;                                      \
-        .pushsection .trampoline_rel, "a"; \
+        .pushsection .bootsym_rel, "a";    \
         .long 111b - (off) - .;            \
         .popsection
 
 #define bootsym_segrel(sym, off)           \
         $0,$bootsym(sym);                  \
 111:;                                      \
-        .pushsection .trampoline_seg, "a"; \
+        .pushsection .bootsym_seg, "a";    \
+        .long 111b - (off) - .;            \
+        .popsection
+
+#define bootdatasym(s) ((s)-trampoline_start)
+#define bootdatasym_rel(sym, off, opnd...) \
+        bootdatasym(sym),##opnd;           \
+111:;                                      \
+        .pushsection .bootdatasym_rel, "a";\
+        .long 111b - (off) - .;            \
+        .popsection
+
+#undef trampsym
+#define trampsym(s) ((s)-trampoline_start)
+
+#define trampsym_rel(sym, off, opnd...)    \
+        trampsym(sym),##opnd;              \
+111:;                                      \
+        .pushsection .trampsym_rel, "a";   \
+        .long 111b - (off) - .;            \
+        .popsection
+
+#undef tramp32sym
+#define tramp32sym(s) ((s)-trampoline_start)
+
+#define tramp32sym_rel(sym, off, opnd...)  \
+        tramp32sym(sym),##opnd;            \
+111:;                                      \
+        .pushsection .tramp32sym_rel, "a"; \
         .long 111b - (off) - .;            \
         .popsection
 
@@ -41,24 +82,28 @@
 GLOBAL(trampoline_realmode_entry)
         mov     %cs,%ax
         mov     %ax,%ds
-        movb    $0xA5,bootsym(trampoline_cpu_started)
+        movb    $0xA5,trampsym(trampoline_cpu_started)
         cld
         cli
-        lidt    bootsym(idt_48)
-        lgdt    bootsym(gdt_48)
+        lidt    trampsym(idt_48)
+        lgdt    trampsym(gdt_48)
         mov     $1,%bl                    # EBX != 0 indicates we are an AP
         xor     %ax, %ax
         inc     %ax
         lmsw    %ax                       # CR0.PE = 1 (enter protected mode)
-        ljmpl   $BOOT_CS32,$bootsym_rel(trampoline_protmode_entry,6)
+        ljmpl   $BOOT_CS32,$tramp32sym_rel(trampoline_protmode_entry,6)
+
+GLOBAL(trampoline_cpu_started)
+        .byte   0
 
         .balign 8
         .word   0
 idt_48: .word   0, 0, 0 # base = limit = 0
         .word   0
 gdt_48: .word   6*8-1
-        .long   bootsym_rel(trampoline_gdt,4)
+        .long   tramp32sym_rel(trampoline_gdt,4)
 
+/* Start of tramp32sym section which can be used in place during boot */
 trampoline_gdt:
         /* 0x0000: unused */
         .quad   0x0000000000000000
@@ -79,8 +124,12 @@ trampoline_gdt:
          * address is computed at runtime.
          */
         .quad   0x00c0920000000fff
-
-        .pushsection .trampoline_rel, "a"
+        /*
+         * BOOT_PSEUDORM_CS and BOOT_PSEUDORM_DS are usable only at boot time,
+         * and their base addresses must reference the low location to which
+         * the boot-time code was loaded. Hence bootsym.
+         */
+        .pushsection .bootsym_rel, "a"
         .long   trampoline_gdt + BOOT_PSEUDORM_CS + 2 - .
         .long   trampoline_gdt + BOOT_PSEUDORM_DS + 2 - .
         .popsection
@@ -94,9 +143,6 @@ GLOBAL(cpuid_ext_features)
 GLOBAL(trampoline_xen_phys_start)
         .long   0
 
-GLOBAL(trampoline_cpu_started)
-        .byte   0
-
         .code32
 trampoline_protmode_entry:
         /* Set up a few descriptors: on entry only CS is guaranteed good. */
@@ -113,12 +159,12 @@ trampoline_protmode_entry:
 
         /* Load pagetable base register. */
         mov     $sym_offs(idle_pg_table),%eax
-        add     bootsym_rel(trampoline_xen_phys_start,4,%eax)
+        add     tramp32sym_rel(trampoline_xen_phys_start,4,%eax)
         mov     %eax,%cr3
 
         /* Adjust IA32_MISC_ENABLE if needed (for NX enabling below). */
-        mov     bootsym_rel(trampoline_misc_enable_off,4,%esi)
-        mov     bootsym_rel(trampoline_misc_enable_off+4,4,%edi)
+        mov     tramp32sym_rel(trampoline_misc_enable_off,4,%esi)
+        mov     tramp32sym_rel(trampoline_misc_enable_off+4,4,%edi)
         mov     %esi,%eax
         or      %edi,%eax
         jz      1f
@@ -132,7 +178,7 @@ trampoline_protmode_entry:
 1:
 
         /* Set up EFER (Extended Feature Enable Register). */
-        mov     bootsym_rel(cpuid_ext_features,4,%edi)
+        mov     tramp32sym_rel(cpuid_ext_features,4,%edi)
         movl    $MSR_EFER,%ecx
         rdmsr
         or      $EFER_LME|EFER_SCE,%eax   /* Long Mode + SYSCALL/SYSRET */
@@ -148,7 +194,7 @@ trampoline_protmode_entry:
 1:
 
         /* Now in compatibility mode. Long-jump into 64-bit mode. */
-        ljmp    $BOOT_CS64,$bootsym_rel(start64,6)
+        ljmp    $BOOT_CS64,$tramp32sym_rel(start64,6)
 
         .code64
 start64:
@@ -242,7 +288,7 @@ trampoline_boot_cpu_entry:
 
         mov     $0x0200,%ax
         int     $0x16
-        mov     %al,bootsym(kbd_shift_flags)
+        mov     %al,bootdatasym(kbd_shift_flags)
 
         /* Disable irqs before returning to protected mode. */
         cli
@@ -287,7 +333,7 @@ opt_edid:
         .byte   0
 
 #ifdef CONFIG_VIDEO
-GLOBAL(boot_vid_mode)
+boot_vid_mode:
         .word   VIDEO_80x25                     /* If we don't run at all, assume basic video mode 3 at 80x25. */
 vesa_size:
         .word   0,0,0                           /* width x depth x height */
diff --git a/xen/arch/x86/boot/video.S b/xen/arch/x86/boot/video.S
index 335a51c9b5..03907e9e9a 100644
--- a/xen/arch/x86/boot/video.S
+++ b/xen/arch/x86/boot/video.S
@@ -45,7 +45,7 @@
 #define PARAM_VESAPM_SEG        0x24
 #define PARAM_VESAPM_OFF        0x26
 #define PARAM_VESA_ATTRIB       0x28
-#define _param(param) bootsym(boot_vid_info)+(param)
+#define _param(param) bootdatasym(boot_vid_info)+(param)
 
 video:  xorw    %ax, %ax
         movw    %ax, %gs        # GS is zero
@@ -917,7 +917,7 @@ store_edid:
         cmpw    $0x004f, %ax            # Call failed?
         jne     .Lno_edid
 
-        movw    %bx, bootsym(boot_edid_caps)
+        movw    %bx, bootdatasym(boot_edid_caps)
 
         cmpb    $2, bootsym(opt_edid)   # EDID forced on cmdline (edid=force)?
         je      .Lforce_edid
@@ -933,7 +933,7 @@ store_edid:
         movw    $0x01, %bx
         movw    $0x00, %cx
         movw    $0x00, %dx
-        movw    $bootsym(boot_edid_info), %di
+        movw    $bootdatasym(boot_edid_info), %di
         int     $0x10
 
 .Lno_edid:
diff --git a/xen/arch/x86/boot/wakeup.S b/xen/arch/x86/boot/wakeup.S
index 8c52819171..1c58e2affb 100644
--- a/xen/arch/x86/boot/wakeup.S
+++ b/xen/arch/x86/boot/wakeup.S
@@ -40,12 +40,12 @@ ENTRY(wakeup_start)
         movw    %ax, %fs
         movw    $0x0e00 + 'L', %fs:(0x10)
 
-        lidt    bootsym(idt_48)
-        lgdt    bootsym(gdt_48)
+        lidt    trampsym(idt_48)
+        lgdt    trampsym(gdt_48)
 
         movw    $1, %ax
         lmsw    %ax             # Turn on CR0.PE 
-        ljmpl   $BOOT_CS32, $bootsym_rel(wakeup_32, 6)
+        ljmpl   $BOOT_CS32, $trampsym_rel(wakeup_32, 6)
 
 /* This code uses an extended set of video mode numbers. These include:
  * Aliases for standard modes
@@ -110,11 +110,11 @@ wakeup_32:
         mov     $BOOT_DS, %eax
         mov     %eax, %ds
         mov     %eax, %ss
-        mov     $bootsym_rel(wakeup_stack, 4, %esp)
+        mov     $trampsym_rel(wakeup_stack, 4, %esp)
 
         # check saved magic again
         mov     $sym_offs(saved_magic),%eax
-        add     bootsym_rel(trampoline_xen_phys_start, 4, %eax)
+        add     trampsym_rel(trampoline_xen_phys_start, 4, %eax)
         mov     (%eax), %eax
         cmp     $0x9abcdef0, %eax
         jne     bogus_saved_magic
@@ -127,12 +127,12 @@ wakeup_32:
 
         /* Load pagetable base register */
         mov     $sym_offs(idle_pg_table),%eax
-        add     bootsym_rel(trampoline_xen_phys_start,4,%eax)
+        add     trampsym_rel(trampoline_xen_phys_start,4,%eax)
         mov     %eax,%cr3
 
         /* Will cpuid feature change after resume? */
         /* Set up EFER (Extended Feature Enable Register). */
-        mov     bootsym_rel(cpuid_ext_features,4,%edi)
+        mov     trampsym_rel(cpuid_ext_features,4,%edi)
         test    $0x20100800,%edi /* SYSCALL/SYSRET, No Execute, Long Mode? */
         jz      .Lskip_eferw
         movl    $MSR_EFER,%ecx
@@ -154,7 +154,7 @@ wakeup_32:
 1:
 
         /* Now in compatibility mode. Long-jump to 64-bit mode */
-        ljmp    $BOOT_CS64, $bootsym_rel(wakeup_64,6)
+        ljmp    $BOOT_CS64, $trampsym_rel(wakeup_64,6)
 
         .code64
 wakeup_64:
diff --git a/xen/arch/x86/efi/efi-boot.h b/xen/arch/x86/efi/efi-boot.h
index 5789d2cb70..abc7d3e3b7 100644
--- a/xen/arch/x86/efi/efi-boot.h
+++ b/xen/arch/x86/efi/efi-boot.h
@@ -99,7 +99,7 @@ static void __init efi_arch_relocate_image(unsigned long delta)
 }
 
 extern const s32 __trampoline_rel_start[], __trampoline_rel_stop[];
-extern const s32 __trampoline_seg_start[], __trampoline_seg_stop[];
+extern const s32 __trampoline32_rel_start[], __trampoline32_rel_stop[];
 
 static void __init relocate_trampoline(unsigned long phys)
 {
@@ -115,10 +115,10 @@ static void __init relocate_trampoline(unsigned long phys)
           trampoline_ptr < __trampoline_rel_stop;
           ++trampoline_ptr )
         *(u32 *)(*trampoline_ptr + (long)trampoline_ptr) += phys;
-    for ( trampoline_ptr = __trampoline_seg_start;
-          trampoline_ptr < __trampoline_seg_stop;
+    for ( trampoline_ptr = __trampoline32_rel_start;
+          trampoline_ptr < __trampoline32_rel_stop;
           ++trampoline_ptr )
-        *(u16 *)(*trampoline_ptr + (long)trampoline_ptr) = phys >> 4;
+        *(u32 *)(*trampoline_ptr + (long)trampoline_ptr) += phys;
 }
 
 static void __init place_string(u32 *addr, const char *s)
diff --git a/xen/arch/x86/xen.lds.S b/xen/arch/x86/xen.lds.S
index a76e2ec8ef..54ac0c0993 100644
--- a/xen/arch/x86/xen.lds.S
+++ b/xen/arch/x86/xen.lds.S
@@ -221,11 +221,18 @@ SECTIONS
        *(.init.data.rel.*)
        . = ALIGN(4);
        __trampoline_rel_start = .;
-       *(.trampoline_rel)
+       *(.trampsym_rel)
        __trampoline_rel_stop = .;
-       __trampoline_seg_start = .;
-       *(.trampoline_seg)
-       __trampoline_seg_stop = .;
+       __trampoline32_rel_start = .;
+       *(.tramp32sym_rel)
+       __trampoline32_rel_stop = .;
+       __bootsym_rel_start = .;
+       *(.bootsym_rel)
+       *(.bootdatasym_rel)
+       __bootsym_rel_stop = .;
+       __bootsym_seg_start = .;
+       *(.bootsym_seg)
+       __bootsym_seg_stop = .;
        /*
         * struct alt_inst entries. From the header (alternative.h):
         * "Alternative instructions for different CPU types or capabilities"
-- 
2.17.2


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^ permalink raw reply related	[flat|nested] 18+ messages in thread

* [RFC PATCH v2 5/7] x86/boot: Rename trampoline_{start, end} to boot_trampoline_{start, end}
@ 2019-05-01 19:39   ` David Woodhouse
  0 siblings, 0 replies; 18+ messages in thread
From: David Woodhouse @ 2019-05-01 19:39 UTC (permalink / raw)
  To: xen-devel

From: David Woodhouse <dwmw@amazon.co.uk>

In preparation for splitting the boot and permanent trampolines from
each other. Some of these will change back, but most are boot so do the
plain search/replace that way first, then a subsequent patch will extract
the permanent trampoline code.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
---
 xen/arch/x86/boot/head.S       | 12 ++++++------
 xen/arch/x86/boot/trampoline.S | 10 +++++-----
 xen/arch/x86/boot/video.S      |  4 ++--
 xen/arch/x86/efi/efi-boot.h    |  4 ++--
 xen/arch/x86/mm.c              |  2 +-
 xen/arch/x86/setup.c           |  4 ++--
 xen/arch/x86/tboot.c           |  6 +++---
 xen/arch/x86/x86_64/mm.c       |  2 +-
 xen/arch/x86/xen.lds.S         |  6 +++---
 xen/include/asm-x86/config.h   |  6 +++---
 10 files changed, 28 insertions(+), 28 deletions(-)

diff --git a/xen/arch/x86/boot/head.S b/xen/arch/x86/boot/head.S
index 5b4f211a9b..82342769c7 100644
--- a/xen/arch/x86/boot/head.S
+++ b/xen/arch/x86/boot/head.S
@@ -753,20 +753,20 @@ trampoline_setup:
         cmpb    $0, sym_fs(skip_realmode)
         jz      1f
         /* If no-real-mode, jump straight to trampoline_protmode_entry */
-        lea     trampoline_protmode_entry-trampoline_start(%edi),%eax
+        lea     trampoline_protmode_entry-boot_trampoline_start(%edi),%eax
         /* EBX == 0 indicates we are the BP (Boot Processor). */
         xor     %ebx,%ebx
         jmp     2f
 1:
         /* Go via 16-bit code in trampoline_boot_cpu_entry */
-        lea     trampoline_boot_cpu_entry-trampoline_start(%edi),%eax
+        lea     trampoline_boot_cpu_entry-boot_trampoline_start(%edi),%eax
 2:
         pushl   $BOOT_CS32
         push    %eax
 
         /* Copy bootstrap trampoline to low memory, below 1MB. */
-        mov     $sym_offs(trampoline_start),%esi
-        mov     $((trampoline_end - trampoline_start) / 4),%ecx
+        mov     $sym_offs(boot_trampoline_start),%esi
+        mov     $((boot_trampoline_end - boot_trampoline_start) / 4),%ecx
         rep movsl %fs:(%esi),%es:(%edi)
 
         /* Jump into the relocated trampoline. */
@@ -778,8 +778,8 @@ cmdline_parse_early:
 reloc:
 #include "reloc.S"
 
-ENTRY(trampoline_start)
+ENTRY(boot_trampoline_start)
 #include "trampoline.S"
-ENTRY(trampoline_end)
+ENTRY(boot_trampoline_end)
 
 #include "x86_64.S"
diff --git a/xen/arch/x86/boot/trampoline.S b/xen/arch/x86/boot/trampoline.S
index e77b4bea36..0f4a740fcb 100644
--- a/xen/arch/x86/boot/trampoline.S
+++ b/xen/arch/x86/boot/trampoline.S
@@ -31,7 +31,7 @@
  *                to be used for AP startup.
  */
 #undef bootsym
-#define bootsym(s) ((s)-trampoline_start)
+#define bootsym(s) ((s)-boot_trampoline_start)
 
 #define bootsym_rel(sym, off, opnd...)     \
         bootsym(sym),##opnd;               \
@@ -47,7 +47,7 @@
         .long 111b - (off) - .;            \
         .popsection
 
-#define bootdatasym(s) ((s)-trampoline_start)
+#define bootdatasym(s) ((s)-boot_trampoline_start)
 #define bootdatasym_rel(sym, off, opnd...) \
         bootdatasym(sym),##opnd;           \
 111:;                                      \
@@ -56,7 +56,7 @@
         .popsection
 
 #undef trampsym
-#define trampsym(s) ((s)-trampoline_start)
+#define trampsym(s) ((s)-boot_trampoline_start)
 
 #define trampsym_rel(sym, off, opnd...)    \
         trampsym(sym),##opnd;              \
@@ -66,7 +66,7 @@
         .popsection
 
 #undef tramp32sym
-#define tramp32sym(s) ((s)-trampoline_start)
+#define tramp32sym(s) ((s)-boot_trampoline_start)
 
 #define tramp32sym_rel(sym, off, opnd...)  \
         tramp32sym(sym),##opnd;            \
@@ -226,7 +226,7 @@ start64:
 
 /* The first page of trampoline is permanent, the rest boot-time only. */
 /* Reuse the boot trampoline on the 1st trampoline page as stack for wakeup. */
-        .equ    wakeup_stack, trampoline_start + PAGE_SIZE
+        .equ    wakeup_stack, boot_trampoline_start + PAGE_SIZE
         .global wakeup_stack
 
 /* From here on early boot only. */
diff --git a/xen/arch/x86/boot/video.S b/xen/arch/x86/boot/video.S
index 03907e9e9a..5087c6a4d5 100644
--- a/xen/arch/x86/boot/video.S
+++ b/xen/arch/x86/boot/video.S
@@ -15,8 +15,8 @@
 
 #include "video.h"
 
-/* Scratch space layout: trampoline_end to trampoline_end+0x1000. */
-#define modelist       bootsym(trampoline_end)   /* 2kB (256 entries) */
+/* Scratch space layout: boot_trampoline_end to boot_trampoline_end+0x1000. */
+#define modelist       bootsym(boot_trampoline_end)   /* 2kB (256 entries) */
 #define vesa_glob_info (modelist + 0x800)        /* 1kB */
 #define vesa_mode_info (vesa_glob_info + 0x400)  /* 1kB */
 
diff --git a/xen/arch/x86/efi/efi-boot.h b/xen/arch/x86/efi/efi-boot.h
index abc7d3e3b7..f6f435a4c5 100644
--- a/xen/arch/x86/efi/efi-boot.h
+++ b/xen/arch/x86/efi/efi-boot.h
@@ -232,7 +232,7 @@ static void __init noreturn efi_arch_post_exit_boot(void)
     u64 cr4 = XEN_MINIMAL_CR4 & ~X86_CR4_PGE, efer;
 
     efi_arch_relocate_image(__XEN_VIRT_START - xen_phys_start);
-    memcpy((void *)trampoline_phys, trampoline_start, cfg.size);
+    memcpy((void *)trampoline_phys, boot_trampoline_start, cfg.size);
 
     /* Set system registers and transfer control. */
     asm volatile("pushq $0\n\tpopfq");
@@ -565,7 +565,7 @@ static void __init efi_arch_memory_setup(void)
     cfg.addr = 0x100000;
 
     if ( efi_enabled(EFI_LOADER) )
-        cfg.size = trampoline_end - trampoline_start;
+        cfg.size = boot_trampoline_end - boot_trampoline_start;
     else
         cfg.size = TRAMPOLINE_SPACE + TRAMPOLINE_STACK_SPACE;
 
diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
index e6a4cb28f8..7a2e188916 100644
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -314,7 +314,7 @@ void __init arch_init_memory(void)
      */
     BUG_ON(pvh_boot && trampoline_phys != 0x1000);
     for ( i = 0;
-          i < (pvh_boot ? (1 + PFN_UP(trampoline_end - trampoline_start))
+          i < (pvh_boot ? (1 + PFN_UP(boot_trampoline_end - boot_trampoline_start))
                         : 0x100);
           i++ )
         share_xen_page_with_guest(mfn_to_page(_mfn(i)), dom_io, SHARE_rw);
diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c
index 5fa7d3b79c..b714e3c237 100644
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -1839,8 +1839,8 @@ int __hwdom_init xen_in_range(unsigned long mfn)
     if ( !xen_regions[0].s )
     {
         /* S3 resume code (and other real mode trampoline code) */
-        xen_regions[region_s3].s = bootsym_phys(trampoline_start);
-        xen_regions[region_s3].e = bootsym_phys(trampoline_end);
+        xen_regions[region_s3].s = bootsym_phys(boot_trampoline_start);
+        xen_regions[region_s3].e = bootsym_phys(boot_trampoline_end);
 
         /*
          * This needs to remain in sync with the uses of the same symbols in
diff --git a/xen/arch/x86/tboot.c b/xen/arch/x86/tboot.c
index fb4616ae83..9e3d9c4c69 100644
--- a/xen/arch/x86/tboot.c
+++ b/xen/arch/x86/tboot.c
@@ -369,9 +369,9 @@ void tboot_shutdown(uint32_t shutdown_type)
          */
         g_tboot_shared->num_mac_regions = 3;
         /* S3 resume code (and other real mode trampoline code) */
-        g_tboot_shared->mac_regions[0].start = bootsym_phys(trampoline_start);
-        g_tboot_shared->mac_regions[0].size = bootsym_phys(trampoline_end) -
-                                              bootsym_phys(trampoline_start);
+        g_tboot_shared->mac_regions[0].start = bootsym_phys(boot_trampoline_start);
+        g_tboot_shared->mac_regions[0].size = bootsym_phys(boot_trampoline_end) -
+                                              bootsym_phys(boot_trampoline_start);
         /* hypervisor .text + .rodata */
         g_tboot_shared->mac_regions[1].start = (uint64_t)__pa(&_stext);
         g_tboot_shared->mac_regions[1].size = __pa(&__2M_rodata_end) -
diff --git a/xen/arch/x86/x86_64/mm.c b/xen/arch/x86/x86_64/mm.c
index cca4ae926e..ffe8ba2086 100644
--- a/xen/arch/x86/x86_64/mm.c
+++ b/xen/arch/x86/x86_64/mm.c
@@ -697,7 +697,7 @@ void __init zap_low_mappings(void)
 
     /* Replace with mapping of the boot trampoline only. */
     map_pages_to_xen(trampoline_phys, maddr_to_mfn(trampoline_phys),
-                     PFN_UP(trampoline_end - trampoline_start),
+                     PFN_UP(boot_trampoline_end - boot_trampoline_start),
                      __PAGE_HYPERVISOR);
 }
 
diff --git a/xen/arch/x86/xen.lds.S b/xen/arch/x86/xen.lds.S
index 54ac0c0993..5f36b88b92 100644
--- a/xen/arch/x86/xen.lds.S
+++ b/xen/arch/x86/xen.lds.S
@@ -361,12 +361,12 @@ ASSERT(IS_ALIGNED(cpu0_stack, STACK_SIZE), "cpu0_stack misaligned")
 ASSERT(IS_ALIGNED(__init_begin, PAGE_SIZE), "__init_begin misaligned")
 ASSERT(IS_ALIGNED(__init_end,   PAGE_SIZE), "__init_end misaligned")
 
-ASSERT(IS_ALIGNED(trampoline_start, 4), "trampoline_start misaligned")
-ASSERT(IS_ALIGNED(trampoline_end,   4), "trampoline_end misaligned")
+ASSERT(IS_ALIGNED(boot_trampoline_start, 4), "boot_trampoline_start misaligned")
+ASSERT(IS_ALIGNED(boot_trampoline_end,   4), "boot_trampoline_end misaligned")
 ASSERT(IS_ALIGNED(__bss_start,      8), "__bss_start misaligned")
 ASSERT(IS_ALIGNED(__bss_end,        8), "__bss_end misaligned")
 
-ASSERT((trampoline_end - trampoline_start) < TRAMPOLINE_SPACE - MBI_SPACE_MIN,
+ASSERT((boot_trampoline_end - boot_trampoline_start) < TRAMPOLINE_SPACE - MBI_SPACE_MIN,
     "not enough room for trampoline and mbi data")
 ASSERT((wakeup_stack - wakeup_stack_start) >= WAKEUP_STACK_MIN,
     "wakeup stack too small")
diff --git a/xen/include/asm-x86/config.h b/xen/include/asm-x86/config.h
index 9ef9d03ca7..9b7ed50825 100644
--- a/xen/include/asm-x86/config.h
+++ b/xen/include/asm-x86/config.h
@@ -91,11 +91,11 @@
 #ifndef __ASSEMBLY__
 extern unsigned long trampoline_phys;
 #define bootsym_phys(sym)                                 \
-    (((unsigned long)&(sym)-(unsigned long)&trampoline_start)+trampoline_phys)
+    (((unsigned long)&(sym)-(unsigned long)&boot_trampoline_start)+trampoline_phys)
 #define bootsym(sym)                                      \
     (*RELOC_HIDE((typeof(&(sym)))__va(__pa(&(sym))),      \
-                 trampoline_phys-__pa(trampoline_start)))
-extern char trampoline_start[], trampoline_end[];
+                 trampoline_phys-__pa(boot_trampoline_start)))
+extern char boot_trampoline_start[], boot_trampoline_end[];
 extern char trampoline_realmode_entry[];
 extern unsigned int trampoline_xen_phys_start;
 extern unsigned char trampoline_cpu_started;
-- 
2.17.2


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Xen-devel@lists.xenproject.org
https://lists.xenproject.org/mailman/listinfo/xen-devel

^ permalink raw reply related	[flat|nested] 18+ messages in thread

* [Xen-devel] [RFC PATCH v2 5/7] x86/boot: Rename trampoline_{start, end} to boot_trampoline_{start, end}
@ 2019-05-01 19:39   ` David Woodhouse
  0 siblings, 0 replies; 18+ messages in thread
From: David Woodhouse @ 2019-05-01 19:39 UTC (permalink / raw)
  To: xen-devel

From: David Woodhouse <dwmw@amazon.co.uk>

In preparation for splitting the boot and permanent trampolines from
each other. Some of these will change back, but most are boot so do the
plain search/replace that way first, then a subsequent patch will extract
the permanent trampoline code.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
---
 xen/arch/x86/boot/head.S       | 12 ++++++------
 xen/arch/x86/boot/trampoline.S | 10 +++++-----
 xen/arch/x86/boot/video.S      |  4 ++--
 xen/arch/x86/efi/efi-boot.h    |  4 ++--
 xen/arch/x86/mm.c              |  2 +-
 xen/arch/x86/setup.c           |  4 ++--
 xen/arch/x86/tboot.c           |  6 +++---
 xen/arch/x86/x86_64/mm.c       |  2 +-
 xen/arch/x86/xen.lds.S         |  6 +++---
 xen/include/asm-x86/config.h   |  6 +++---
 10 files changed, 28 insertions(+), 28 deletions(-)

diff --git a/xen/arch/x86/boot/head.S b/xen/arch/x86/boot/head.S
index 5b4f211a9b..82342769c7 100644
--- a/xen/arch/x86/boot/head.S
+++ b/xen/arch/x86/boot/head.S
@@ -753,20 +753,20 @@ trampoline_setup:
         cmpb    $0, sym_fs(skip_realmode)
         jz      1f
         /* If no-real-mode, jump straight to trampoline_protmode_entry */
-        lea     trampoline_protmode_entry-trampoline_start(%edi),%eax
+        lea     trampoline_protmode_entry-boot_trampoline_start(%edi),%eax
         /* EBX == 0 indicates we are the BP (Boot Processor). */
         xor     %ebx,%ebx
         jmp     2f
 1:
         /* Go via 16-bit code in trampoline_boot_cpu_entry */
-        lea     trampoline_boot_cpu_entry-trampoline_start(%edi),%eax
+        lea     trampoline_boot_cpu_entry-boot_trampoline_start(%edi),%eax
 2:
         pushl   $BOOT_CS32
         push    %eax
 
         /* Copy bootstrap trampoline to low memory, below 1MB. */
-        mov     $sym_offs(trampoline_start),%esi
-        mov     $((trampoline_end - trampoline_start) / 4),%ecx
+        mov     $sym_offs(boot_trampoline_start),%esi
+        mov     $((boot_trampoline_end - boot_trampoline_start) / 4),%ecx
         rep movsl %fs:(%esi),%es:(%edi)
 
         /* Jump into the relocated trampoline. */
@@ -778,8 +778,8 @@ cmdline_parse_early:
 reloc:
 #include "reloc.S"
 
-ENTRY(trampoline_start)
+ENTRY(boot_trampoline_start)
 #include "trampoline.S"
-ENTRY(trampoline_end)
+ENTRY(boot_trampoline_end)
 
 #include "x86_64.S"
diff --git a/xen/arch/x86/boot/trampoline.S b/xen/arch/x86/boot/trampoline.S
index e77b4bea36..0f4a740fcb 100644
--- a/xen/arch/x86/boot/trampoline.S
+++ b/xen/arch/x86/boot/trampoline.S
@@ -31,7 +31,7 @@
  *                to be used for AP startup.
  */
 #undef bootsym
-#define bootsym(s) ((s)-trampoline_start)
+#define bootsym(s) ((s)-boot_trampoline_start)
 
 #define bootsym_rel(sym, off, opnd...)     \
         bootsym(sym),##opnd;               \
@@ -47,7 +47,7 @@
         .long 111b - (off) - .;            \
         .popsection
 
-#define bootdatasym(s) ((s)-trampoline_start)
+#define bootdatasym(s) ((s)-boot_trampoline_start)
 #define bootdatasym_rel(sym, off, opnd...) \
         bootdatasym(sym),##opnd;           \
 111:;                                      \
@@ -56,7 +56,7 @@
         .popsection
 
 #undef trampsym
-#define trampsym(s) ((s)-trampoline_start)
+#define trampsym(s) ((s)-boot_trampoline_start)
 
 #define trampsym_rel(sym, off, opnd...)    \
         trampsym(sym),##opnd;              \
@@ -66,7 +66,7 @@
         .popsection
 
 #undef tramp32sym
-#define tramp32sym(s) ((s)-trampoline_start)
+#define tramp32sym(s) ((s)-boot_trampoline_start)
 
 #define tramp32sym_rel(sym, off, opnd...)  \
         tramp32sym(sym),##opnd;            \
@@ -226,7 +226,7 @@ start64:
 
 /* The first page of trampoline is permanent, the rest boot-time only. */
 /* Reuse the boot trampoline on the 1st trampoline page as stack for wakeup. */
-        .equ    wakeup_stack, trampoline_start + PAGE_SIZE
+        .equ    wakeup_stack, boot_trampoline_start + PAGE_SIZE
         .global wakeup_stack
 
 /* From here on early boot only. */
diff --git a/xen/arch/x86/boot/video.S b/xen/arch/x86/boot/video.S
index 03907e9e9a..5087c6a4d5 100644
--- a/xen/arch/x86/boot/video.S
+++ b/xen/arch/x86/boot/video.S
@@ -15,8 +15,8 @@
 
 #include "video.h"
 
-/* Scratch space layout: trampoline_end to trampoline_end+0x1000. */
-#define modelist       bootsym(trampoline_end)   /* 2kB (256 entries) */
+/* Scratch space layout: boot_trampoline_end to boot_trampoline_end+0x1000. */
+#define modelist       bootsym(boot_trampoline_end)   /* 2kB (256 entries) */
 #define vesa_glob_info (modelist + 0x800)        /* 1kB */
 #define vesa_mode_info (vesa_glob_info + 0x400)  /* 1kB */
 
diff --git a/xen/arch/x86/efi/efi-boot.h b/xen/arch/x86/efi/efi-boot.h
index abc7d3e3b7..f6f435a4c5 100644
--- a/xen/arch/x86/efi/efi-boot.h
+++ b/xen/arch/x86/efi/efi-boot.h
@@ -232,7 +232,7 @@ static void __init noreturn efi_arch_post_exit_boot(void)
     u64 cr4 = XEN_MINIMAL_CR4 & ~X86_CR4_PGE, efer;
 
     efi_arch_relocate_image(__XEN_VIRT_START - xen_phys_start);
-    memcpy((void *)trampoline_phys, trampoline_start, cfg.size);
+    memcpy((void *)trampoline_phys, boot_trampoline_start, cfg.size);
 
     /* Set system registers and transfer control. */
     asm volatile("pushq $0\n\tpopfq");
@@ -565,7 +565,7 @@ static void __init efi_arch_memory_setup(void)
     cfg.addr = 0x100000;
 
     if ( efi_enabled(EFI_LOADER) )
-        cfg.size = trampoline_end - trampoline_start;
+        cfg.size = boot_trampoline_end - boot_trampoline_start;
     else
         cfg.size = TRAMPOLINE_SPACE + TRAMPOLINE_STACK_SPACE;
 
diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
index e6a4cb28f8..7a2e188916 100644
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -314,7 +314,7 @@ void __init arch_init_memory(void)
      */
     BUG_ON(pvh_boot && trampoline_phys != 0x1000);
     for ( i = 0;
-          i < (pvh_boot ? (1 + PFN_UP(trampoline_end - trampoline_start))
+          i < (pvh_boot ? (1 + PFN_UP(boot_trampoline_end - boot_trampoline_start))
                         : 0x100);
           i++ )
         share_xen_page_with_guest(mfn_to_page(_mfn(i)), dom_io, SHARE_rw);
diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c
index 5fa7d3b79c..b714e3c237 100644
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -1839,8 +1839,8 @@ int __hwdom_init xen_in_range(unsigned long mfn)
     if ( !xen_regions[0].s )
     {
         /* S3 resume code (and other real mode trampoline code) */
-        xen_regions[region_s3].s = bootsym_phys(trampoline_start);
-        xen_regions[region_s3].e = bootsym_phys(trampoline_end);
+        xen_regions[region_s3].s = bootsym_phys(boot_trampoline_start);
+        xen_regions[region_s3].e = bootsym_phys(boot_trampoline_end);
 
         /*
          * This needs to remain in sync with the uses of the same symbols in
diff --git a/xen/arch/x86/tboot.c b/xen/arch/x86/tboot.c
index fb4616ae83..9e3d9c4c69 100644
--- a/xen/arch/x86/tboot.c
+++ b/xen/arch/x86/tboot.c
@@ -369,9 +369,9 @@ void tboot_shutdown(uint32_t shutdown_type)
          */
         g_tboot_shared->num_mac_regions = 3;
         /* S3 resume code (and other real mode trampoline code) */
-        g_tboot_shared->mac_regions[0].start = bootsym_phys(trampoline_start);
-        g_tboot_shared->mac_regions[0].size = bootsym_phys(trampoline_end) -
-                                              bootsym_phys(trampoline_start);
+        g_tboot_shared->mac_regions[0].start = bootsym_phys(boot_trampoline_start);
+        g_tboot_shared->mac_regions[0].size = bootsym_phys(boot_trampoline_end) -
+                                              bootsym_phys(boot_trampoline_start);
         /* hypervisor .text + .rodata */
         g_tboot_shared->mac_regions[1].start = (uint64_t)__pa(&_stext);
         g_tboot_shared->mac_regions[1].size = __pa(&__2M_rodata_end) -
diff --git a/xen/arch/x86/x86_64/mm.c b/xen/arch/x86/x86_64/mm.c
index cca4ae926e..ffe8ba2086 100644
--- a/xen/arch/x86/x86_64/mm.c
+++ b/xen/arch/x86/x86_64/mm.c
@@ -697,7 +697,7 @@ void __init zap_low_mappings(void)
 
     /* Replace with mapping of the boot trampoline only. */
     map_pages_to_xen(trampoline_phys, maddr_to_mfn(trampoline_phys),
-                     PFN_UP(trampoline_end - trampoline_start),
+                     PFN_UP(boot_trampoline_end - boot_trampoline_start),
                      __PAGE_HYPERVISOR);
 }
 
diff --git a/xen/arch/x86/xen.lds.S b/xen/arch/x86/xen.lds.S
index 54ac0c0993..5f36b88b92 100644
--- a/xen/arch/x86/xen.lds.S
+++ b/xen/arch/x86/xen.lds.S
@@ -361,12 +361,12 @@ ASSERT(IS_ALIGNED(cpu0_stack, STACK_SIZE), "cpu0_stack misaligned")
 ASSERT(IS_ALIGNED(__init_begin, PAGE_SIZE), "__init_begin misaligned")
 ASSERT(IS_ALIGNED(__init_end,   PAGE_SIZE), "__init_end misaligned")
 
-ASSERT(IS_ALIGNED(trampoline_start, 4), "trampoline_start misaligned")
-ASSERT(IS_ALIGNED(trampoline_end,   4), "trampoline_end misaligned")
+ASSERT(IS_ALIGNED(boot_trampoline_start, 4), "boot_trampoline_start misaligned")
+ASSERT(IS_ALIGNED(boot_trampoline_end,   4), "boot_trampoline_end misaligned")
 ASSERT(IS_ALIGNED(__bss_start,      8), "__bss_start misaligned")
 ASSERT(IS_ALIGNED(__bss_end,        8), "__bss_end misaligned")
 
-ASSERT((trampoline_end - trampoline_start) < TRAMPOLINE_SPACE - MBI_SPACE_MIN,
+ASSERT((boot_trampoline_end - boot_trampoline_start) < TRAMPOLINE_SPACE - MBI_SPACE_MIN,
     "not enough room for trampoline and mbi data")
 ASSERT((wakeup_stack - wakeup_stack_start) >= WAKEUP_STACK_MIN,
     "wakeup stack too small")
diff --git a/xen/include/asm-x86/config.h b/xen/include/asm-x86/config.h
index 9ef9d03ca7..9b7ed50825 100644
--- a/xen/include/asm-x86/config.h
+++ b/xen/include/asm-x86/config.h
@@ -91,11 +91,11 @@
 #ifndef __ASSEMBLY__
 extern unsigned long trampoline_phys;
 #define bootsym_phys(sym)                                 \
-    (((unsigned long)&(sym)-(unsigned long)&trampoline_start)+trampoline_phys)
+    (((unsigned long)&(sym)-(unsigned long)&boot_trampoline_start)+trampoline_phys)
 #define bootsym(sym)                                      \
     (*RELOC_HIDE((typeof(&(sym)))__va(__pa(&(sym))),      \
-                 trampoline_phys-__pa(trampoline_start)))
-extern char trampoline_start[], trampoline_end[];
+                 trampoline_phys-__pa(boot_trampoline_start)))
+extern char boot_trampoline_start[], boot_trampoline_end[];
 extern char trampoline_realmode_entry[];
 extern unsigned int trampoline_xen_phys_start;
 extern unsigned char trampoline_cpu_started;
-- 
2.17.2


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https://lists.xenproject.org/mailman/listinfo/xen-devel

^ permalink raw reply related	[flat|nested] 18+ messages in thread

* [RFC PATCH v2 6/7] x86/boot: Copy 16-bit boot variables back up to Xen image
@ 2019-05-01 19:39   ` David Woodhouse
  0 siblings, 0 replies; 18+ messages in thread
From: David Woodhouse @ 2019-05-01 19:39 UTC (permalink / raw)
  To: xen-devel

From: David Woodhouse <dwmw@amazon.co.uk>

Ditch the bootsym() access from C code for the variables populated by
16-bit boot code. As well as being cleaner this also paves the way for
not having the 16-bit boot code in low memory for no-real-mode or EFI
loader boots at all.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
---
 xen/arch/x86/boot/edd.S           |  2 ++
 xen/arch/x86/boot/head.S          | 16 +++++++++++++++
 xen/arch/x86/boot/mem.S           |  2 ++
 xen/arch/x86/boot/trampoline.S    | 33 ++++++++++++++++++++++++++++---
 xen/arch/x86/boot/video.S         | 30 +++++++++++++++-------------
 xen/arch/x86/platform_hypercall.c | 18 ++++++++---------
 xen/arch/x86/setup.c              | 23 +++++++++++----------
 xen/arch/x86/xen.lds.S            |  8 +++++++-
 xen/include/asm-x86/edd.h         |  1 -
 9 files changed, 93 insertions(+), 40 deletions(-)

diff --git a/xen/arch/x86/boot/edd.S b/xen/arch/x86/boot/edd.S
index 434bbbd960..138d04c964 100644
--- a/xen/arch/x86/boot/edd.S
+++ b/xen/arch/x86/boot/edd.S
@@ -163,6 +163,7 @@ edd_done:
 .Ledd_mbr_sig_skip:
         ret
 
+        .pushsection .data.boot16, "aw", @progbits
 GLOBAL(boot_edd_info_nr)
         .byte   0
 GLOBAL(boot_mbr_signature_nr)
@@ -171,3 +172,4 @@ GLOBAL(boot_mbr_signature)
         .fill   EDD_MBR_SIG_MAX*8,1,0
 GLOBAL(boot_edd_info)
         .fill   EDD_INFO_MAX * (EDDEXTSIZE + EDDPARMSIZE), 1, 0
+        .popsection
diff --git a/xen/arch/x86/boot/head.S b/xen/arch/x86/boot/head.S
index 82342769c7..7d6c8d3292 100644
--- a/xen/arch/x86/boot/head.S
+++ b/xen/arch/x86/boot/head.S
@@ -732,6 +732,17 @@ trampoline_setup:
         cmp     $sym_offs(__bootsym_seg_stop),%edi
         jb      1b
 
+        /* Relocations for the boot data section. */
+        mov     sym_fs(trampoline_phys),%edx
+        add     $(boot_trampoline_end - boot_trampoline_start),%edx
+        mov     $sym_offs(__bootdatasym_rel_start),%edi
+1:
+        mov     %fs:(%edi),%eax
+        add     %edx,%fs:(%edi,%eax)
+        add     $4,%edi
+        cmp     $sym_offs(__bootdatasym_rel_stop),%edi
+        jb      1b
+
         /* Do not parse command line on EFI platform here. */
         cmpb    $0,sym_fs(efi_platform)
         jnz     1f
@@ -769,6 +780,11 @@ trampoline_setup:
         mov     $((boot_trampoline_end - boot_trampoline_start) / 4),%ecx
         rep movsl %fs:(%esi),%es:(%edi)
 
+        /* Copy boot data template to low memory. */
+        mov     $sym_offs(bootdata_start),%esi
+        mov     $((bootdata_end - bootdata_start + 3) / 4),%ecx
+        rep movsl %fs:(%esi),%es:(%edi)
+
         /* Jump into the relocated trampoline. */
         lret
 
diff --git a/xen/arch/x86/boot/mem.S b/xen/arch/x86/boot/mem.S
index aa39608442..86f0fa9af7 100644
--- a/xen/arch/x86/boot/mem.S
+++ b/xen/arch/x86/boot/mem.S
@@ -67,6 +67,7 @@ get_memory_map:
         ret
 
         .align  4
+        .pushsection .data.boot16, "aw", @progbits
 GLOBAL(bios_e820map)
         .fill   E820_BIOS_MAX*20,1,0
 GLOBAL(bios_e820nr)
@@ -75,3 +76,4 @@ GLOBAL(lowmem_kb)
         .long   0
 GLOBAL(highmem_kb)
         .long   0
+	.popsection
diff --git a/xen/arch/x86/boot/trampoline.S b/xen/arch/x86/boot/trampoline.S
index 0f4a740fcb..fdfee2edb1 100644
--- a/xen/arch/x86/boot/trampoline.S
+++ b/xen/arch/x86/boot/trampoline.S
@@ -47,11 +47,15 @@
         .long 111b - (off) - .;            \
         .popsection
 
-#define bootdatasym(s) ((s)-boot_trampoline_start)
+        .pushsection .data.boot16, "aw", @progbits
+GLOBAL(bootdata_start)
+        .popsection
+
+#define bootdatasym(s) ((s)-bootdata_start+(boot_trampoline_end-boot_trampoline_start))
 #define bootdatasym_rel(sym, off, opnd...) \
         bootdatasym(sym),##opnd;           \
 111:;                                      \
-        .pushsection .bootdatasym_rel, "a";\
+        .pushsection .bootsym_rel, "a";\
         .long 111b - (off) - .;            \
         .popsection
 
@@ -100,7 +104,7 @@ GLOBAL(trampoline_cpu_started)
         .word   0
 idt_48: .word   0, 0, 0 # base = limit = 0
         .word   0
-gdt_48: .word   6*8-1
+gdt_48: .word   7*8-1
         .long   tramp32sym_rel(trampoline_gdt,4)
 
 /* Start of tramp32sym section which can be used in place during boot */
@@ -312,6 +316,23 @@ trampoline_boot_cpu_entry:
         mov     %eax,%gs
         mov     %eax,%ss
 
+        /*
+         * Copy locally-gathered data back up into the Xen physical image
+         */
+        mov     $BOOT_FS,%eax
+        mov     %eax,%es
+
+        mov     $sym_offs(bootdata_end),%ecx
+        mov     $sym_offs(bootdata_start),%edi
+        sub     %edi,%ecx
+        mov     $bootdatasym_rel(bootdata_start,4,%esi)
+        rep movsb %ds:(%esi),%es:(%edi)
+
+        /*
+         * %es still points to BOOT_FS but trampoline_protmode_entry
+         * reloads it anyway.
+         */
+
         /* EBX == 0 indicates we are the BP (Boot Processor). */
         xor     %ebx,%ebx
 
@@ -339,8 +360,10 @@ vesa_size:
         .word   0,0,0                           /* width x depth x height */
 #endif
 
+        .pushsection .data.boot16, "aw", @progbits
 GLOBAL(kbd_shift_flags)
         .byte   0
+        .popsection
 
 rm_idt: .word   256*4-1, 0, 0
 
@@ -349,3 +372,7 @@ rm_idt: .word   256*4-1, 0, 0
 #ifdef CONFIG_VIDEO
 #include "video.S"
 #endif
+
+        .pushsection .data.boot16, "aw", @progbits
+GLOBAL(bootdata_end)
+        .popsection
diff --git a/xen/arch/x86/boot/video.S b/xen/arch/x86/boot/video.S
index 5087c6a4d5..4608464b77 100644
--- a/xen/arch/x86/boot/video.S
+++ b/xen/arch/x86/boot/video.S
@@ -15,10 +15,10 @@
 
 #include "video.h"
 
-/* Scratch space layout: boot_trampoline_end to boot_trampoline_end+0x1000. */
-#define modelist       bootsym(boot_trampoline_end)   /* 2kB (256 entries) */
-#define vesa_glob_info (modelist + 0x800)        /* 1kB */
-#define vesa_mode_info (vesa_glob_info + 0x400)  /* 1kB */
+/* Scratch space layout: bootdata_end to bootdata_end+0x1000. */
+#define modelist(t)       bootdatasym_rel(bootdata_end,2,t)         /* 2KiB (256 entries) */
+#define vesa_glob_info(t) bootdatasym_rel((bootdata_end+0x800),2,t) /* 1KiB */
+#define vesa_mode_info(t) bootdatasym_rel((bootdata_end+0xc00),2,t) /* 1KiB */
 
 /* Retrieve Extended Display Identification Data. */
 #define CONFIG_FIRMWARE_EDID
@@ -113,7 +113,7 @@ mopar2: movb    %al, _param(PARAM_VIDEO_LINES)
 
 # Fetching of VESA frame buffer parameters
 mopar_gr:
-        leaw    vesa_mode_info, %di
+        leaw    vesa_mode_info(%di)
         movb    $0x23, _param(PARAM_HAVE_VGA)
         movw    16(%di), %ax
         movw    %ax, _param(PARAM_LFB_LINELENGTH)
@@ -134,7 +134,7 @@ mopar_gr:
         movw    %ax, _param(PARAM_VESA_ATTRIB)
 
 # get video mem size
-        leaw    vesa_glob_info, %di
+        leaw    vesa_glob_info(%di)
         xorl    %eax, %eax
         movw    18(%di), %ax
         movl    %eax, _param(PARAM_LFB_SIZE)
@@ -226,7 +226,7 @@ an1:    call    prtstr
         leaw    bootsym(listhdr), %si   # Table header
         call    prtstr
         movb    $0x30, %dl              # DL holds mode number
-        leaw    modelist, %si
+        leaw    modelist(%si)
 lm1:    cmpw    $ASK_VGA, (%si)         # End?
         jz      lm2
 
@@ -435,13 +435,13 @@ setmenu:
         jmp     mode_set
 
 check_vesa:
-        leaw    vesa_glob_info, %di
+        leaw    vesa_glob_info(%di)
         movw    $0x4f00, %ax
         int     $0x10
         cmpw    $0x004f, %ax
         jnz     setbad
 
-        leaw    vesa_mode_info, %di
+        leaw    vesa_mode_info(%di)
         subb    $VIDEO_FIRST_VESA>>8, %bh
         movw    %bx, %cx                # Get mode information structure
         movw    $0x4f01, %ax
@@ -509,7 +509,7 @@ inidx:  outb    %al, %dx                # Read from indexed VGA register
 
 setvesabysize:
         call    mode_table
-        leaw    modelist,%si
+        leaw    modelist(%si)
 1:      add     $8,%si
         cmpw    $ASK_VGA,-8(%si)        # End?
         je      _setbad
@@ -669,7 +669,7 @@ mode_table:
         orw     %di, %di
         jnz     mtab1
 
-        leaw    modelist, %di           # Store standard modes:
+        leaw    modelist(%di)           # Store standard modes:
         movw    $VIDEO_80x25,(%di)      # The 80x25 mode (ALL)
         movw    $0x50,2(%di)
         movw    $0x19,4(%di)
@@ -684,7 +684,7 @@ mode_table:
 
         movw    $ASK_VGA, (%di)         # End marker
         movw    %di, bootsym(mt_end)
-mtab1:  leaw    modelist, %si           # SI=mode list, DI=list end
+mtab1:  leaw    modelist(%si)           # SI=mode list, DI=list end
 ret0:   ret
 
 # Modes usable on all standard VGAs
@@ -700,7 +700,7 @@ vga_modes_end:
 # Detect VESA modes.
 vesa_modes:
         movw    %di, %bp                # BP=original mode table end
-        leaw    vesa_glob_info, %di
+        leaw    vesa_glob_info(%di)
         movw    $0x4f00, %ax            # VESA Get card info call
         int     $0x10
         movw    %di, %si
@@ -897,7 +897,7 @@ store_edid:
         cmpb    $1, bootsym(opt_edid)   # EDID disabled on cmdline (edid=no)?
         je      .Lno_edid
 
-        leaw    vesa_glob_info, %di
+        leaw    vesa_glob_info(%di)
         movw    $0x4f00, %ax
         int     $0x10
         cmpw    $0x004f, %ax
@@ -990,6 +990,7 @@ name_bann:      .asciz  "Video adapter: "
 
 force_size:     .word   0       # Use this size instead of the one in BIOS vars
 
+        .pushsection .data.boot16, "aw", @progbits
 GLOBAL(boot_vid_info)
         .byte   0, 0    /* orig_x, orig_y */
         .byte   3       /* text mode 3    */
@@ -1001,3 +1002,4 @@ GLOBAL(boot_edid_info)
         .fill   128,1,0x13
 GLOBAL(boot_edid_caps)
         .word   0x1313
+        .popsection
diff --git a/xen/arch/x86/platform_hypercall.c b/xen/arch/x86/platform_hypercall.c
index ea18c3215a..5c8953ae19 100644
--- a/xen/arch/x86/platform_hypercall.c
+++ b/xen/arch/x86/platform_hypercall.c
@@ -333,10 +333,10 @@ ret_t do_platform_op(XEN_GUEST_HANDLE_PARAM(xen_platform_op_t) u_xenpf_op)
             u16 length;
 
             ret = -ESRCH;
-            if ( op->u.firmware_info.index >= bootsym(boot_edd_info_nr) )
+            if ( op->u.firmware_info.index >= boot_edd_info_nr )
                 break;
 
-            info = bootsym(boot_edd_info) + op->u.firmware_info.index;
+            info = boot_edd_info + op->u.firmware_info.index;
 
             /* Transfer the EDD info block. */
             ret = -EFAULT;
@@ -372,10 +372,10 @@ ret_t do_platform_op(XEN_GUEST_HANDLE_PARAM(xen_platform_op_t) u_xenpf_op)
             const struct mbr_signature *sig;
 
             ret = -ESRCH;
-            if ( op->u.firmware_info.index >= bootsym(boot_mbr_signature_nr) )
+            if ( op->u.firmware_info.index >= boot_mbr_signature_nr )
                 break;
 
-            sig = bootsym(boot_mbr_signature) + op->u.firmware_info.index;
+            sig = boot_mbr_signature + op->u.firmware_info.index;
 
             op->u.firmware_info.u.disk_mbr_signature.device = sig->device;
             op->u.firmware_info.u.disk_mbr_signature.mbr_signature =
@@ -391,13 +391,13 @@ ret_t do_platform_op(XEN_GUEST_HANDLE_PARAM(xen_platform_op_t) u_xenpf_op)
 #ifdef CONFIG_VIDEO
             if ( op->u.firmware_info.index != 0 )
                 break;
-            if ( *(u32 *)bootsym(boot_edid_info) == 0x13131313 )
+            if ( *(u32 *)boot_edid_info == 0x13131313 )
                 break;
 
             op->u.firmware_info.u.vbeddc_info.capabilities =
-                bootsym(boot_edid_caps);
+                boot_edid_caps;
             op->u.firmware_info.u.vbeddc_info.edid_transfer_time =
-                bootsym(boot_edid_caps) >> 8;
+                boot_edid_caps >> 8;
 
             ret = 0;
             if ( __copy_field_to_guest(u_xenpf_op, op, u.firmware_info.
@@ -405,7 +405,7 @@ ret_t do_platform_op(XEN_GUEST_HANDLE_PARAM(xen_platform_op_t) u_xenpf_op)
                  __copy_field_to_guest(u_xenpf_op, op, u.firmware_info.
                                        u.vbeddc_info.edid_transfer_time) ||
                  copy_to_compat(op->u.firmware_info.u.vbeddc_info.edid,
-                                bootsym(boot_edid_info), 128) )
+                                boot_edid_info, 128) )
                 ret = -EFAULT;
 #endif
             break;
@@ -422,7 +422,7 @@ ret_t do_platform_op(XEN_GUEST_HANDLE_PARAM(xen_platform_op_t) u_xenpf_op)
             if ( op->u.firmware_info.index != 0 )
                 break;
 
-            op->u.firmware_info.u.kbd_shift_flags = bootsym(kbd_shift_flags);
+            op->u.firmware_info.u.kbd_shift_flags = kbd_shift_flags;
 
             ret = 0;
             if ( __copy_field_to_guest(u_xenpf_op, op,
diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c
index b714e3c237..4dd4c4161c 100644
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -507,7 +507,7 @@ extern struct boot_video_info boot_vid_info;
 static void __init parse_video_info(void)
 {
 #ifdef CONFIG_VIDEO
-    struct boot_video_info *bvi = &bootsym(boot_vid_info);
+    struct boot_video_info *bvi = &boot_vid_info;
 
     /* vga_console_info is filled directly on EFI platform. */
     if ( efi_enabled(EFI_BOOT) )
@@ -666,12 +666,11 @@ static char * __init cmdline_cook(char *p, const char *loader_name)
 
 static int copy_bios_e820(struct e820entry *map, unsigned int limit)
 {
-    unsigned int n = bootsym(bios_e820nr);
+    unsigned int n = bios_e820nr;
     if (n > limit)
         n = limit;
-
     if (n)
-        memcpy(map, bootsym(bios_e820map), sizeof(*map) * n);
+        memcpy(map, bios_e820map, sizeof(*map) * n);
 
     return n;
 }
@@ -802,15 +801,15 @@ void __init noreturn __start_xen(unsigned long mbi_p)
     }
 
     /* Print VBE/DDC EDID information. */
-    if ( bootsym(boot_edid_caps) != 0x1313 )
+    if ( boot_edid_caps != 0x1313 )
     {
-        u16 caps = bootsym(boot_edid_caps);
+        u16 caps = boot_edid_caps;
         printk(" VBE/DDC methods:%s%s%s; ",
                (caps & 1) ? " V1" : "",
                (caps & 2) ? " V2" : "",
                !(caps & 3) ? " none" : "");
         printk("EDID transfer time: %d seconds\n", caps >> 8);
-        if ( *(u32 *)bootsym(boot_edid_info) == 0x13131313 )
+        if ( *(u32 *)boot_edid_info == 0x13131313 )
         {
             printk(" EDID info not retrieved because ");
             if ( !(caps & 3) )
@@ -825,9 +824,9 @@ void __init noreturn __start_xen(unsigned long mbi_p)
 
     printk("Disc information:\n");
     printk(" Found %d MBR signatures\n",
-           bootsym(boot_mbr_signature_nr));
+           boot_mbr_signature_nr);
     printk(" Found %d EDD information structures\n",
-           bootsym(boot_edd_info_nr));
+           boot_edd_info_nr);
 
     /* Check that we have at least one Multiboot module. */
     if ( !(mbi->flags & MBI_MODULES) || (mbi->mods_count == 0) )
@@ -899,14 +898,14 @@ void __init noreturn __start_xen(unsigned long mbi_p)
             bytes += map->size + 4;
         }
     }
-    else if ( bootsym(lowmem_kb) )
+    else if ( lowmem_kb )
     {
         memmap_type = "Xen-e801";
         e820_raw.map[0].addr = 0;
-        e820_raw.map[0].size = bootsym(lowmem_kb) << 10;
+        e820_raw.map[0].size = lowmem_kb << 10;
         e820_raw.map[0].type = E820_RAM;
         e820_raw.map[1].addr = 0x100000;
-        e820_raw.map[1].size = bootsym(highmem_kb) << 10;
+        e820_raw.map[1].size = highmem_kb << 10;
         e820_raw.map[1].type = E820_RAM;
         e820_raw.nr_map = 2;
     }
diff --git a/xen/arch/x86/xen.lds.S b/xen/arch/x86/xen.lds.S
index 5f36b88b92..436781cefa 100644
--- a/xen/arch/x86/xen.lds.S
+++ b/xen/arch/x86/xen.lds.S
@@ -228,11 +228,13 @@ SECTIONS
        __trampoline32_rel_stop = .;
        __bootsym_rel_start = .;
        *(.bootsym_rel)
-       *(.bootdatasym_rel)
        __bootsym_rel_stop = .;
        __bootsym_seg_start = .;
        *(.bootsym_seg)
        __bootsym_seg_stop = .;
+       __bootdatasym_rel_start = .;
+       *(.bootdatasym_rel)
+       __bootdatasym_rel_stop = .;
        /*
         * struct alt_inst entries. From the header (alternative.h):
         * "Alternative instructions for different CPU types or capabilities"
@@ -275,6 +277,10 @@ SECTIONS
   DECL_SECTION(.data) {
        *(.data.page_aligned)
        *(.data)
+       . = ALIGN(16);
+       __bootdata_start = .;
+       *(.data.boot16)
+       __bootdata_end = .;
        *(.data.rel)
        *(.data.rel.*)
        CONSTRUCTORS
diff --git a/xen/include/asm-x86/edd.h b/xen/include/asm-x86/edd.h
index afaa23732a..a4d6b4d90e 100644
--- a/xen/include/asm-x86/edd.h
+++ b/xen/include/asm-x86/edd.h
@@ -143,7 +143,6 @@ struct __packed mbr_signature {
     u32 signature;
 };
 
-/* These all reside in the boot trampoline. Access via bootsym(). */
 extern struct mbr_signature boot_mbr_signature[];
 extern u8 boot_mbr_signature_nr;
 extern struct edd_info boot_edd_info[];
-- 
2.17.2


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^ permalink raw reply related	[flat|nested] 18+ messages in thread

* [Xen-devel] [RFC PATCH v2 6/7] x86/boot: Copy 16-bit boot variables back up to Xen image
@ 2019-05-01 19:39   ` David Woodhouse
  0 siblings, 0 replies; 18+ messages in thread
From: David Woodhouse @ 2019-05-01 19:39 UTC (permalink / raw)
  To: xen-devel

From: David Woodhouse <dwmw@amazon.co.uk>

Ditch the bootsym() access from C code for the variables populated by
16-bit boot code. As well as being cleaner this also paves the way for
not having the 16-bit boot code in low memory for no-real-mode or EFI
loader boots at all.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
---
 xen/arch/x86/boot/edd.S           |  2 ++
 xen/arch/x86/boot/head.S          | 16 +++++++++++++++
 xen/arch/x86/boot/mem.S           |  2 ++
 xen/arch/x86/boot/trampoline.S    | 33 ++++++++++++++++++++++++++++---
 xen/arch/x86/boot/video.S         | 30 +++++++++++++++-------------
 xen/arch/x86/platform_hypercall.c | 18 ++++++++---------
 xen/arch/x86/setup.c              | 23 +++++++++++----------
 xen/arch/x86/xen.lds.S            |  8 +++++++-
 xen/include/asm-x86/edd.h         |  1 -
 9 files changed, 93 insertions(+), 40 deletions(-)

diff --git a/xen/arch/x86/boot/edd.S b/xen/arch/x86/boot/edd.S
index 434bbbd960..138d04c964 100644
--- a/xen/arch/x86/boot/edd.S
+++ b/xen/arch/x86/boot/edd.S
@@ -163,6 +163,7 @@ edd_done:
 .Ledd_mbr_sig_skip:
         ret
 
+        .pushsection .data.boot16, "aw", @progbits
 GLOBAL(boot_edd_info_nr)
         .byte   0
 GLOBAL(boot_mbr_signature_nr)
@@ -171,3 +172,4 @@ GLOBAL(boot_mbr_signature)
         .fill   EDD_MBR_SIG_MAX*8,1,0
 GLOBAL(boot_edd_info)
         .fill   EDD_INFO_MAX * (EDDEXTSIZE + EDDPARMSIZE), 1, 0
+        .popsection
diff --git a/xen/arch/x86/boot/head.S b/xen/arch/x86/boot/head.S
index 82342769c7..7d6c8d3292 100644
--- a/xen/arch/x86/boot/head.S
+++ b/xen/arch/x86/boot/head.S
@@ -732,6 +732,17 @@ trampoline_setup:
         cmp     $sym_offs(__bootsym_seg_stop),%edi
         jb      1b
 
+        /* Relocations for the boot data section. */
+        mov     sym_fs(trampoline_phys),%edx
+        add     $(boot_trampoline_end - boot_trampoline_start),%edx
+        mov     $sym_offs(__bootdatasym_rel_start),%edi
+1:
+        mov     %fs:(%edi),%eax
+        add     %edx,%fs:(%edi,%eax)
+        add     $4,%edi
+        cmp     $sym_offs(__bootdatasym_rel_stop),%edi
+        jb      1b
+
         /* Do not parse command line on EFI platform here. */
         cmpb    $0,sym_fs(efi_platform)
         jnz     1f
@@ -769,6 +780,11 @@ trampoline_setup:
         mov     $((boot_trampoline_end - boot_trampoline_start) / 4),%ecx
         rep movsl %fs:(%esi),%es:(%edi)
 
+        /* Copy boot data template to low memory. */
+        mov     $sym_offs(bootdata_start),%esi
+        mov     $((bootdata_end - bootdata_start + 3) / 4),%ecx
+        rep movsl %fs:(%esi),%es:(%edi)
+
         /* Jump into the relocated trampoline. */
         lret
 
diff --git a/xen/arch/x86/boot/mem.S b/xen/arch/x86/boot/mem.S
index aa39608442..86f0fa9af7 100644
--- a/xen/arch/x86/boot/mem.S
+++ b/xen/arch/x86/boot/mem.S
@@ -67,6 +67,7 @@ get_memory_map:
         ret
 
         .align  4
+        .pushsection .data.boot16, "aw", @progbits
 GLOBAL(bios_e820map)
         .fill   E820_BIOS_MAX*20,1,0
 GLOBAL(bios_e820nr)
@@ -75,3 +76,4 @@ GLOBAL(lowmem_kb)
         .long   0
 GLOBAL(highmem_kb)
         .long   0
+	.popsection
diff --git a/xen/arch/x86/boot/trampoline.S b/xen/arch/x86/boot/trampoline.S
index 0f4a740fcb..fdfee2edb1 100644
--- a/xen/arch/x86/boot/trampoline.S
+++ b/xen/arch/x86/boot/trampoline.S
@@ -47,11 +47,15 @@
         .long 111b - (off) - .;            \
         .popsection
 
-#define bootdatasym(s) ((s)-boot_trampoline_start)
+        .pushsection .data.boot16, "aw", @progbits
+GLOBAL(bootdata_start)
+        .popsection
+
+#define bootdatasym(s) ((s)-bootdata_start+(boot_trampoline_end-boot_trampoline_start))
 #define bootdatasym_rel(sym, off, opnd...) \
         bootdatasym(sym),##opnd;           \
 111:;                                      \
-        .pushsection .bootdatasym_rel, "a";\
+        .pushsection .bootsym_rel, "a";\
         .long 111b - (off) - .;            \
         .popsection
 
@@ -100,7 +104,7 @@ GLOBAL(trampoline_cpu_started)
         .word   0
 idt_48: .word   0, 0, 0 # base = limit = 0
         .word   0
-gdt_48: .word   6*8-1
+gdt_48: .word   7*8-1
         .long   tramp32sym_rel(trampoline_gdt,4)
 
 /* Start of tramp32sym section which can be used in place during boot */
@@ -312,6 +316,23 @@ trampoline_boot_cpu_entry:
         mov     %eax,%gs
         mov     %eax,%ss
 
+        /*
+         * Copy locally-gathered data back up into the Xen physical image
+         */
+        mov     $BOOT_FS,%eax
+        mov     %eax,%es
+
+        mov     $sym_offs(bootdata_end),%ecx
+        mov     $sym_offs(bootdata_start),%edi
+        sub     %edi,%ecx
+        mov     $bootdatasym_rel(bootdata_start,4,%esi)
+        rep movsb %ds:(%esi),%es:(%edi)
+
+        /*
+         * %es still points to BOOT_FS but trampoline_protmode_entry
+         * reloads it anyway.
+         */
+
         /* EBX == 0 indicates we are the BP (Boot Processor). */
         xor     %ebx,%ebx
 
@@ -339,8 +360,10 @@ vesa_size:
         .word   0,0,0                           /* width x depth x height */
 #endif
 
+        .pushsection .data.boot16, "aw", @progbits
 GLOBAL(kbd_shift_flags)
         .byte   0
+        .popsection
 
 rm_idt: .word   256*4-1, 0, 0
 
@@ -349,3 +372,7 @@ rm_idt: .word   256*4-1, 0, 0
 #ifdef CONFIG_VIDEO
 #include "video.S"
 #endif
+
+        .pushsection .data.boot16, "aw", @progbits
+GLOBAL(bootdata_end)
+        .popsection
diff --git a/xen/arch/x86/boot/video.S b/xen/arch/x86/boot/video.S
index 5087c6a4d5..4608464b77 100644
--- a/xen/arch/x86/boot/video.S
+++ b/xen/arch/x86/boot/video.S
@@ -15,10 +15,10 @@
 
 #include "video.h"
 
-/* Scratch space layout: boot_trampoline_end to boot_trampoline_end+0x1000. */
-#define modelist       bootsym(boot_trampoline_end)   /* 2kB (256 entries) */
-#define vesa_glob_info (modelist + 0x800)        /* 1kB */
-#define vesa_mode_info (vesa_glob_info + 0x400)  /* 1kB */
+/* Scratch space layout: bootdata_end to bootdata_end+0x1000. */
+#define modelist(t)       bootdatasym_rel(bootdata_end,2,t)         /* 2KiB (256 entries) */
+#define vesa_glob_info(t) bootdatasym_rel((bootdata_end+0x800),2,t) /* 1KiB */
+#define vesa_mode_info(t) bootdatasym_rel((bootdata_end+0xc00),2,t) /* 1KiB */
 
 /* Retrieve Extended Display Identification Data. */
 #define CONFIG_FIRMWARE_EDID
@@ -113,7 +113,7 @@ mopar2: movb    %al, _param(PARAM_VIDEO_LINES)
 
 # Fetching of VESA frame buffer parameters
 mopar_gr:
-        leaw    vesa_mode_info, %di
+        leaw    vesa_mode_info(%di)
         movb    $0x23, _param(PARAM_HAVE_VGA)
         movw    16(%di), %ax
         movw    %ax, _param(PARAM_LFB_LINELENGTH)
@@ -134,7 +134,7 @@ mopar_gr:
         movw    %ax, _param(PARAM_VESA_ATTRIB)
 
 # get video mem size
-        leaw    vesa_glob_info, %di
+        leaw    vesa_glob_info(%di)
         xorl    %eax, %eax
         movw    18(%di), %ax
         movl    %eax, _param(PARAM_LFB_SIZE)
@@ -226,7 +226,7 @@ an1:    call    prtstr
         leaw    bootsym(listhdr), %si   # Table header
         call    prtstr
         movb    $0x30, %dl              # DL holds mode number
-        leaw    modelist, %si
+        leaw    modelist(%si)
 lm1:    cmpw    $ASK_VGA, (%si)         # End?
         jz      lm2
 
@@ -435,13 +435,13 @@ setmenu:
         jmp     mode_set
 
 check_vesa:
-        leaw    vesa_glob_info, %di
+        leaw    vesa_glob_info(%di)
         movw    $0x4f00, %ax
         int     $0x10
         cmpw    $0x004f, %ax
         jnz     setbad
 
-        leaw    vesa_mode_info, %di
+        leaw    vesa_mode_info(%di)
         subb    $VIDEO_FIRST_VESA>>8, %bh
         movw    %bx, %cx                # Get mode information structure
         movw    $0x4f01, %ax
@@ -509,7 +509,7 @@ inidx:  outb    %al, %dx                # Read from indexed VGA register
 
 setvesabysize:
         call    mode_table
-        leaw    modelist,%si
+        leaw    modelist(%si)
 1:      add     $8,%si
         cmpw    $ASK_VGA,-8(%si)        # End?
         je      _setbad
@@ -669,7 +669,7 @@ mode_table:
         orw     %di, %di
         jnz     mtab1
 
-        leaw    modelist, %di           # Store standard modes:
+        leaw    modelist(%di)           # Store standard modes:
         movw    $VIDEO_80x25,(%di)      # The 80x25 mode (ALL)
         movw    $0x50,2(%di)
         movw    $0x19,4(%di)
@@ -684,7 +684,7 @@ mode_table:
 
         movw    $ASK_VGA, (%di)         # End marker
         movw    %di, bootsym(mt_end)
-mtab1:  leaw    modelist, %si           # SI=mode list, DI=list end
+mtab1:  leaw    modelist(%si)           # SI=mode list, DI=list end
 ret0:   ret
 
 # Modes usable on all standard VGAs
@@ -700,7 +700,7 @@ vga_modes_end:
 # Detect VESA modes.
 vesa_modes:
         movw    %di, %bp                # BP=original mode table end
-        leaw    vesa_glob_info, %di
+        leaw    vesa_glob_info(%di)
         movw    $0x4f00, %ax            # VESA Get card info call
         int     $0x10
         movw    %di, %si
@@ -897,7 +897,7 @@ store_edid:
         cmpb    $1, bootsym(opt_edid)   # EDID disabled on cmdline (edid=no)?
         je      .Lno_edid
 
-        leaw    vesa_glob_info, %di
+        leaw    vesa_glob_info(%di)
         movw    $0x4f00, %ax
         int     $0x10
         cmpw    $0x004f, %ax
@@ -990,6 +990,7 @@ name_bann:      .asciz  "Video adapter: "
 
 force_size:     .word   0       # Use this size instead of the one in BIOS vars
 
+        .pushsection .data.boot16, "aw", @progbits
 GLOBAL(boot_vid_info)
         .byte   0, 0    /* orig_x, orig_y */
         .byte   3       /* text mode 3    */
@@ -1001,3 +1002,4 @@ GLOBAL(boot_edid_info)
         .fill   128,1,0x13
 GLOBAL(boot_edid_caps)
         .word   0x1313
+        .popsection
diff --git a/xen/arch/x86/platform_hypercall.c b/xen/arch/x86/platform_hypercall.c
index ea18c3215a..5c8953ae19 100644
--- a/xen/arch/x86/platform_hypercall.c
+++ b/xen/arch/x86/platform_hypercall.c
@@ -333,10 +333,10 @@ ret_t do_platform_op(XEN_GUEST_HANDLE_PARAM(xen_platform_op_t) u_xenpf_op)
             u16 length;
 
             ret = -ESRCH;
-            if ( op->u.firmware_info.index >= bootsym(boot_edd_info_nr) )
+            if ( op->u.firmware_info.index >= boot_edd_info_nr )
                 break;
 
-            info = bootsym(boot_edd_info) + op->u.firmware_info.index;
+            info = boot_edd_info + op->u.firmware_info.index;
 
             /* Transfer the EDD info block. */
             ret = -EFAULT;
@@ -372,10 +372,10 @@ ret_t do_platform_op(XEN_GUEST_HANDLE_PARAM(xen_platform_op_t) u_xenpf_op)
             const struct mbr_signature *sig;
 
             ret = -ESRCH;
-            if ( op->u.firmware_info.index >= bootsym(boot_mbr_signature_nr) )
+            if ( op->u.firmware_info.index >= boot_mbr_signature_nr )
                 break;
 
-            sig = bootsym(boot_mbr_signature) + op->u.firmware_info.index;
+            sig = boot_mbr_signature + op->u.firmware_info.index;
 
             op->u.firmware_info.u.disk_mbr_signature.device = sig->device;
             op->u.firmware_info.u.disk_mbr_signature.mbr_signature =
@@ -391,13 +391,13 @@ ret_t do_platform_op(XEN_GUEST_HANDLE_PARAM(xen_platform_op_t) u_xenpf_op)
 #ifdef CONFIG_VIDEO
             if ( op->u.firmware_info.index != 0 )
                 break;
-            if ( *(u32 *)bootsym(boot_edid_info) == 0x13131313 )
+            if ( *(u32 *)boot_edid_info == 0x13131313 )
                 break;
 
             op->u.firmware_info.u.vbeddc_info.capabilities =
-                bootsym(boot_edid_caps);
+                boot_edid_caps;
             op->u.firmware_info.u.vbeddc_info.edid_transfer_time =
-                bootsym(boot_edid_caps) >> 8;
+                boot_edid_caps >> 8;
 
             ret = 0;
             if ( __copy_field_to_guest(u_xenpf_op, op, u.firmware_info.
@@ -405,7 +405,7 @@ ret_t do_platform_op(XEN_GUEST_HANDLE_PARAM(xen_platform_op_t) u_xenpf_op)
                  __copy_field_to_guest(u_xenpf_op, op, u.firmware_info.
                                        u.vbeddc_info.edid_transfer_time) ||
                  copy_to_compat(op->u.firmware_info.u.vbeddc_info.edid,
-                                bootsym(boot_edid_info), 128) )
+                                boot_edid_info, 128) )
                 ret = -EFAULT;
 #endif
             break;
@@ -422,7 +422,7 @@ ret_t do_platform_op(XEN_GUEST_HANDLE_PARAM(xen_platform_op_t) u_xenpf_op)
             if ( op->u.firmware_info.index != 0 )
                 break;
 
-            op->u.firmware_info.u.kbd_shift_flags = bootsym(kbd_shift_flags);
+            op->u.firmware_info.u.kbd_shift_flags = kbd_shift_flags;
 
             ret = 0;
             if ( __copy_field_to_guest(u_xenpf_op, op,
diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c
index b714e3c237..4dd4c4161c 100644
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -507,7 +507,7 @@ extern struct boot_video_info boot_vid_info;
 static void __init parse_video_info(void)
 {
 #ifdef CONFIG_VIDEO
-    struct boot_video_info *bvi = &bootsym(boot_vid_info);
+    struct boot_video_info *bvi = &boot_vid_info;
 
     /* vga_console_info is filled directly on EFI platform. */
     if ( efi_enabled(EFI_BOOT) )
@@ -666,12 +666,11 @@ static char * __init cmdline_cook(char *p, const char *loader_name)
 
 static int copy_bios_e820(struct e820entry *map, unsigned int limit)
 {
-    unsigned int n = bootsym(bios_e820nr);
+    unsigned int n = bios_e820nr;
     if (n > limit)
         n = limit;
-
     if (n)
-        memcpy(map, bootsym(bios_e820map), sizeof(*map) * n);
+        memcpy(map, bios_e820map, sizeof(*map) * n);
 
     return n;
 }
@@ -802,15 +801,15 @@ void __init noreturn __start_xen(unsigned long mbi_p)
     }
 
     /* Print VBE/DDC EDID information. */
-    if ( bootsym(boot_edid_caps) != 0x1313 )
+    if ( boot_edid_caps != 0x1313 )
     {
-        u16 caps = bootsym(boot_edid_caps);
+        u16 caps = boot_edid_caps;
         printk(" VBE/DDC methods:%s%s%s; ",
                (caps & 1) ? " V1" : "",
                (caps & 2) ? " V2" : "",
                !(caps & 3) ? " none" : "");
         printk("EDID transfer time: %d seconds\n", caps >> 8);
-        if ( *(u32 *)bootsym(boot_edid_info) == 0x13131313 )
+        if ( *(u32 *)boot_edid_info == 0x13131313 )
         {
             printk(" EDID info not retrieved because ");
             if ( !(caps & 3) )
@@ -825,9 +824,9 @@ void __init noreturn __start_xen(unsigned long mbi_p)
 
     printk("Disc information:\n");
     printk(" Found %d MBR signatures\n",
-           bootsym(boot_mbr_signature_nr));
+           boot_mbr_signature_nr);
     printk(" Found %d EDD information structures\n",
-           bootsym(boot_edd_info_nr));
+           boot_edd_info_nr);
 
     /* Check that we have at least one Multiboot module. */
     if ( !(mbi->flags & MBI_MODULES) || (mbi->mods_count == 0) )
@@ -899,14 +898,14 @@ void __init noreturn __start_xen(unsigned long mbi_p)
             bytes += map->size + 4;
         }
     }
-    else if ( bootsym(lowmem_kb) )
+    else if ( lowmem_kb )
     {
         memmap_type = "Xen-e801";
         e820_raw.map[0].addr = 0;
-        e820_raw.map[0].size = bootsym(lowmem_kb) << 10;
+        e820_raw.map[0].size = lowmem_kb << 10;
         e820_raw.map[0].type = E820_RAM;
         e820_raw.map[1].addr = 0x100000;
-        e820_raw.map[1].size = bootsym(highmem_kb) << 10;
+        e820_raw.map[1].size = highmem_kb << 10;
         e820_raw.map[1].type = E820_RAM;
         e820_raw.nr_map = 2;
     }
diff --git a/xen/arch/x86/xen.lds.S b/xen/arch/x86/xen.lds.S
index 5f36b88b92..436781cefa 100644
--- a/xen/arch/x86/xen.lds.S
+++ b/xen/arch/x86/xen.lds.S
@@ -228,11 +228,13 @@ SECTIONS
        __trampoline32_rel_stop = .;
        __bootsym_rel_start = .;
        *(.bootsym_rel)
-       *(.bootdatasym_rel)
        __bootsym_rel_stop = .;
        __bootsym_seg_start = .;
        *(.bootsym_seg)
        __bootsym_seg_stop = .;
+       __bootdatasym_rel_start = .;
+       *(.bootdatasym_rel)
+       __bootdatasym_rel_stop = .;
        /*
         * struct alt_inst entries. From the header (alternative.h):
         * "Alternative instructions for different CPU types or capabilities"
@@ -275,6 +277,10 @@ SECTIONS
   DECL_SECTION(.data) {
        *(.data.page_aligned)
        *(.data)
+       . = ALIGN(16);
+       __bootdata_start = .;
+       *(.data.boot16)
+       __bootdata_end = .;
        *(.data.rel)
        *(.data.rel.*)
        CONSTRUCTORS
diff --git a/xen/include/asm-x86/edd.h b/xen/include/asm-x86/edd.h
index afaa23732a..a4d6b4d90e 100644
--- a/xen/include/asm-x86/edd.h
+++ b/xen/include/asm-x86/edd.h
@@ -143,7 +143,6 @@ struct __packed mbr_signature {
     u32 signature;
 };
 
-/* These all reside in the boot trampoline. Access via bootsym(). */
 extern struct mbr_signature boot_mbr_signature[];
 extern u8 boot_mbr_signature_nr;
 extern struct edd_info boot_edd_info[];
-- 
2.17.2


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^ permalink raw reply related	[flat|nested] 18+ messages in thread

* [RFC PATCH v2 7/7] x86/boot: Do not use trampoline for no-real-mode boot paths
@ 2019-05-01 19:39   ` David Woodhouse
  0 siblings, 0 replies; 18+ messages in thread
From: David Woodhouse @ 2019-05-01 19:39 UTC (permalink / raw)
  To: xen-devel

From: David Woodhouse <dwmw@amazon.co.uk>

Where booted from EFI or with no-real-mode, there is no need to stomp
on low memory with the 16-boot code. Instead, just go straight to
trampoline_protmode_entry() at its physical location within the Xen
image.

For now, the boot code (including the EFI loader path) still determines
what the trampoline_phys address should be. The trampoline is actually
relocated for that address and copied into low memory, from a
relocate_trampoline() call made from __start_xen().

For subsequent AP startup and wakeup, the 32-bit trampoline can't
trivially be used in-place as that region isn't mapped. So copy it
down to low memory too, having relocated it (again) to work from
there.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
---
 xen/arch/x86/acpi/power.c      |  6 +--
 xen/arch/x86/boot/head.S       | 67 ++++++++++++++++------------------
 xen/arch/x86/boot/trampoline.S | 30 +++++++++++----
 xen/arch/x86/cpu/common.c      |  2 +-
 xen/arch/x86/cpu/intel.c       |  2 +-
 xen/arch/x86/efi/efi-boot.h    | 31 ++--------------
 xen/arch/x86/mm.c              |  2 +-
 xen/arch/x86/setup.c           | 43 ++++++++++++++++++++--
 xen/arch/x86/smpboot.c         |  6 +--
 xen/arch/x86/tboot.c           |  6 +--
 xen/arch/x86/x86_64/mm.c       |  2 +-
 xen/include/asm-x86/acpi.h     |  2 +-
 xen/include/asm-x86/config.h   | 10 ++---
 13 files changed, 117 insertions(+), 92 deletions(-)

diff --git a/xen/arch/x86/acpi/power.c b/xen/arch/x86/acpi/power.c
index a704c7c340..a1ce8acb21 100644
--- a/xen/arch/x86/acpi/power.c
+++ b/xen/arch/x86/acpi/power.c
@@ -152,9 +152,9 @@ static void acpi_sleep_prepare(u32 state)
         return;
 
     if ( acpi_sinfo.vector_width == 32 )
-        *(uint32_t *)wakeup_vector_va = bootsym_phys(wakeup_start);
+        *(uint32_t *)wakeup_vector_va = trampsym_phys(wakeup_start);
     else
-        *(uint64_t *)wakeup_vector_va = bootsym_phys(wakeup_start);
+        *(uint64_t *)wakeup_vector_va = trampsym_phys(wakeup_start);
 }
 
 static void acpi_sleep_post(u32 state) {}
@@ -388,7 +388,7 @@ static void tboot_sleep(u8 sleep_state)
     g_tboot_shared->acpi_sinfo.wakeup_vector = acpi_sinfo.wakeup_vector;
     g_tboot_shared->acpi_sinfo.vector_width = acpi_sinfo.vector_width;
     g_tboot_shared->acpi_sinfo.kernel_s3_resume_vector =
-                                              bootsym_phys(wakeup_start);
+                                              trampsym_phys(wakeup_start);
 
     switch ( sleep_state )
     {
diff --git a/xen/arch/x86/boot/head.S b/xen/arch/x86/boot/head.S
index 7d6c8d3292..c23eeb3aa4 100644
--- a/xen/arch/x86/boot/head.S
+++ b/xen/arch/x86/boot/head.S
@@ -696,16 +696,23 @@ trampoline_setup:
         lea     __PAGE_HYPERVISOR+sym_esi(l1_identmap),%edi
         mov     %edi,sym_fs(l2_bootmap)
 
-        /* Apply relocations to bootstrap trampoline. */
-        mov     sym_fs(trampoline_phys),%edx
-        mov     $sym_offs(__trampoline_rel_start),%edi
-1:
-        mov     %fs:(%edi),%eax
-        add     %edx,%fs:(%edi,%eax)
-        add     $4,%edi
-        cmp     $sym_offs(__trampoline_rel_stop),%edi
-        jb      1b
+        /* Do not parse command line on EFI platform here. */
+        cmpb    $0,sym_fs(efi_platform)
+        jnz     1f
 
+        /* Bail if there is no command line to parse. */
+        mov     sym_fs(multiboot_ptr),%ebx
+        testl   $MBI_CMDLINE,MB_flags(%ebx)
+        jz      1f
+
+        lea     sym_esi(early_boot_opts),%eax
+        push    %eax
+        pushl   MB_cmdline(%ebx)
+        call    cmdline_parse_early
+
+1:
+        /* Apply relocations to 32-bit trampoline for execution in place. */
+        lea     sym_esi(perm_trampoline_start),%edx
         mov     $sym_offs(__trampoline32_rel_start),%edi
 1:
         mov     %fs:(%edi),%eax
@@ -714,6 +721,21 @@ trampoline_setup:
         cmp     $sym_offs(__trampoline32_rel_stop),%edi
         jb      1b
 
+        cmp     $0,sym_esi(skip_realmode)
+        jz      .Ldo_realmode
+
+        /* Go directly to trampoline_protmode_entry at its physical address */
+        lea     trampoline_protmode_entry-__XEN_VIRT_START(%esi),%eax
+        pushl   $BOOT_CS32
+        push    %eax
+
+        /* EBX == 0 indicates we are the BP (Boot Processor). */
+        xor     %ebx,%ebx
+        retl
+
+.Ldo_realmode:
+        /* Apply relocations to 16-bit boot code. */
+        mov     sym_fs(trampoline_phys),%edx
         mov     $sym_offs(__bootsym_rel_start),%edi
 1:
         mov     %fs:(%edi),%eax
@@ -743,35 +765,12 @@ trampoline_setup:
         cmp     $sym_offs(__bootdatasym_rel_stop),%edi
         jb      1b
 
-        /* Do not parse command line on EFI platform here. */
-        cmpb    $0,sym_fs(efi_platform)
-        jnz     1f
-
-        /* Bail if there is no command line to parse. */
-        mov     sym_fs(multiboot_ptr),%ebx
-        testl   $MBI_CMDLINE,MB_flags(%ebx)
-        jz      1f
-
-        lea     sym_esi(early_boot_opts),%eax
-        push    %eax
-        pushl   MB_cmdline(%ebx)
-        call    cmdline_parse_early
-
-1:
         /* Switch to low-memory stack which lives at the end of trampoline region. */
         mov     sym_fs(trampoline_phys),%edi
         lea     TRAMPOLINE_SPACE+TRAMPOLINE_STACK_SPACE(%edi),%esp
-        cmpb    $0, sym_fs(skip_realmode)
-        jz      1f
-        /* If no-real-mode, jump straight to trampoline_protmode_entry */
-        lea     trampoline_protmode_entry-boot_trampoline_start(%edi),%eax
-        /* EBX == 0 indicates we are the BP (Boot Processor). */
-        xor     %ebx,%ebx
-        jmp     2f
-1:
+
         /* Go via 16-bit code in trampoline_boot_cpu_entry */
         lea     trampoline_boot_cpu_entry-boot_trampoline_start(%edi),%eax
-2:
         pushl   $BOOT_CS32
         push    %eax
 
@@ -794,8 +793,6 @@ cmdline_parse_early:
 reloc:
 #include "reloc.S"
 
-ENTRY(boot_trampoline_start)
 #include "trampoline.S"
-ENTRY(boot_trampoline_end)
 
 #include "x86_64.S"
diff --git a/xen/arch/x86/boot/trampoline.S b/xen/arch/x86/boot/trampoline.S
index fdfee2edb1..1ce815e0da 100644
--- a/xen/arch/x86/boot/trampoline.S
+++ b/xen/arch/x86/boot/trampoline.S
@@ -60,7 +60,7 @@ GLOBAL(bootdata_start)
         .popsection
 
 #undef trampsym
-#define trampsym(s) ((s)-boot_trampoline_start)
+#define trampsym(s) ((s)-perm_trampoline_start)
 
 #define trampsym_rel(sym, off, opnd...)    \
         trampsym(sym),##opnd;              \
@@ -70,7 +70,7 @@ GLOBAL(bootdata_start)
         .popsection
 
 #undef tramp32sym
-#define tramp32sym(s) ((s)-boot_trampoline_start)
+#define tramp32sym(s) ((s)-perm_trampoline_start)
 
 #define tramp32sym_rel(sym, off, opnd...)  \
         tramp32sym(sym),##opnd;            \
@@ -83,6 +83,7 @@ GLOBAL(bootdata_start)
 
         .code16
 
+ENTRY(perm_trampoline_start)
 GLOBAL(trampoline_realmode_entry)
         mov     %cs,%ax
         mov     %ax,%ds
@@ -90,7 +91,7 @@ GLOBAL(trampoline_realmode_entry)
         cld
         cli
         lidt    trampsym(idt_48)
-        lgdt    trampsym(gdt_48)
+        lgdtl   trampsym(gdt_48)
         mov     $1,%bl                    # EBX != 0 indicates we are an AP
         xor     %ax, %ax
         inc     %ax
@@ -230,11 +231,23 @@ start64:
 
 /* The first page of trampoline is permanent, the rest boot-time only. */
 /* Reuse the boot trampoline on the 1st trampoline page as stack for wakeup. */
-        .equ    wakeup_stack, boot_trampoline_start + PAGE_SIZE
+        .equ    wakeup_stack, perm_trampoline_start + PAGE_SIZE
         .global wakeup_stack
 
+ENTRY(perm_trampoline_end)
+
 /* From here on early boot only. */
 
+ENTRY(boot_trampoline_start)
+
+        .word   0
+boot16_idt:
+        .word   0, 0, 0 # base = limit = 0
+        .word   0
+boot16_gdt:
+        .word   7*8-1
+        .long   tramp32sym_rel(trampoline_gdt,4)
+
         .code32
 trampoline_boot_cpu_entry:
         /* Load pseudo-real-mode segments. */
@@ -298,8 +311,8 @@ trampoline_boot_cpu_entry:
         cli
 
         /* Reset GDT and IDT. Some BIOSes clobber GDTR. */
-        lidt    bootsym(idt_48)
-        lgdt    bootsym(gdt_48)
+        lidt    bootsym(boot16_idt) # XXX
+        lgdtl   bootsym(boot16_gdt)
 
         /* Enter protected mode, and flush insn queue. */
         xor     %ax,%ax
@@ -337,7 +350,8 @@ trampoline_boot_cpu_entry:
         xor     %ebx,%ebx
 
         /* Jump to the common bootstrap entry point. */
-        jmp     trampoline_protmode_entry
+        mov     $tramp32sym_rel(trampoline_protmode_entry,4,%eax)
+        jmp     *%eax
 
 #include "video.h"
 
@@ -373,6 +387,8 @@ rm_idt: .word   256*4-1, 0, 0
 #include "video.S"
 #endif
 
+ENTRY(boot_trampoline_end)
+
         .pushsection .data.boot16, "aw", @progbits
 GLOBAL(bootdata_end)
         .popsection
diff --git a/xen/arch/x86/cpu/common.c b/xen/arch/x86/cpu/common.c
index 1d21ff9467..b268e010c5 100644
--- a/xen/arch/x86/cpu/common.c
+++ b/xen/arch/x86/cpu/common.c
@@ -408,7 +408,7 @@ static void generic_identify(struct cpuinfo_x86 *c)
 		      &c->x86_capability[cpufeat_word(X86_FEATURE_LAHF_LM)],
 		      &c->x86_capability[cpufeat_word(X86_FEATURE_SYSCALL)]);
 	if (c == &boot_cpu_data)
-		bootsym(cpuid_ext_features) =
+		trampsym(cpuid_ext_features) =
 			c->x86_capability[cpufeat_word(X86_FEATURE_NX)];
 
 	if (c->extended_cpuid_level >= 0x80000004)
diff --git a/xen/arch/x86/cpu/intel.c b/xen/arch/x86/cpu/intel.c
index 8e23ed6379..e7f794a601 100644
--- a/xen/arch/x86/cpu/intel.c
+++ b/xen/arch/x86/cpu/intel.c
@@ -240,7 +240,7 @@ static void early_init_intel(struct cpuinfo_x86 *c)
 				 MSR_IA32_MISC_ENABLE_XD_DISABLE);
 	if (disable) {
 		wrmsrl(MSR_IA32_MISC_ENABLE, misc_enable & ~disable);
-		bootsym(trampoline_misc_enable_off) |= disable;
+		trampsym(trampoline_misc_enable_off) |= disable;
 	}
 
 	if (disable & MSR_IA32_MISC_ENABLE_LIMIT_CPUID)
diff --git a/xen/arch/x86/efi/efi-boot.h b/xen/arch/x86/efi/efi-boot.h
index f6f435a4c5..ecec334d60 100644
--- a/xen/arch/x86/efi/efi-boot.h
+++ b/xen/arch/x86/efi/efi-boot.h
@@ -98,29 +98,6 @@ static void __init efi_arch_relocate_image(unsigned long delta)
     }
 }
 
-extern const s32 __trampoline_rel_start[], __trampoline_rel_stop[];
-extern const s32 __trampoline32_rel_start[], __trampoline32_rel_stop[];
-
-static void __init relocate_trampoline(unsigned long phys)
-{
-    const s32 *trampoline_ptr;
-
-    trampoline_phys = phys;
-
-    if ( !efi_enabled(EFI_LOADER) )
-        return;
-
-    /* Apply relocations to trampoline. */
-    for ( trampoline_ptr = __trampoline_rel_start;
-          trampoline_ptr < __trampoline_rel_stop;
-          ++trampoline_ptr )
-        *(u32 *)(*trampoline_ptr + (long)trampoline_ptr) += phys;
-    for ( trampoline_ptr = __trampoline32_rel_start;
-          trampoline_ptr < __trampoline32_rel_stop;
-          ++trampoline_ptr )
-        *(u32 *)(*trampoline_ptr + (long)trampoline_ptr) += phys;
-}
-
 static void __init place_string(u32 *addr, const char *s)
 {
     char *alloc = NULL;
@@ -223,7 +200,7 @@ static void __init efi_arch_pre_exit_boot(void)
     {
         if ( !cfg.addr )
             blexit(L"No memory for trampoline");
-        relocate_trampoline(cfg.addr);
+        trampoline_phys = cfg.addr;
     }
 }
 
@@ -232,7 +209,6 @@ static void __init noreturn efi_arch_post_exit_boot(void)
     u64 cr4 = XEN_MINIMAL_CR4 & ~X86_CR4_PGE, efer;
 
     efi_arch_relocate_image(__XEN_VIRT_START - xen_phys_start);
-    memcpy((void *)trampoline_phys, boot_trampoline_start, cfg.size);
 
     /* Set system registers and transfer control. */
     asm volatile("pushq $0\n\tpopfq");
@@ -565,14 +541,14 @@ static void __init efi_arch_memory_setup(void)
     cfg.addr = 0x100000;
 
     if ( efi_enabled(EFI_LOADER) )
-        cfg.size = boot_trampoline_end - boot_trampoline_start;
+        cfg.size = perm_trampoline_end - perm_trampoline_start;
     else
         cfg.size = TRAMPOLINE_SPACE + TRAMPOLINE_STACK_SPACE;
 
     status = efi_bs->AllocatePages(AllocateMaxAddress, EfiLoaderData,
                                    PFN_UP(cfg.size), &cfg.addr);
     if ( status == EFI_SUCCESS )
-        relocate_trampoline(cfg.addr);
+        trampoline_phys = cfg.addr;
     else
     {
         cfg.addr = 0;
@@ -664,7 +640,6 @@ static void __init efi_arch_load_addr_check(EFI_LOADED_IMAGE *loaded_image)
         blexit(L"Xen must be loaded below 4Gb.");
     if ( xen_phys_start & ((1 << L2_PAGETABLE_SHIFT) - 1) )
         blexit(L"Xen must be loaded at a 2Mb boundary.");
-    trampoline_xen_phys_start = xen_phys_start;
 }
 
 static bool __init efi_arch_use_config_file(EFI_SYSTEM_TABLE *SystemTable)
diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
index 7a2e188916..17a55b4b8a 100644
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -314,7 +314,7 @@ void __init arch_init_memory(void)
      */
     BUG_ON(pvh_boot && trampoline_phys != 0x1000);
     for ( i = 0;
-          i < (pvh_boot ? (1 + PFN_UP(boot_trampoline_end - boot_trampoline_start))
+          i < (pvh_boot ? (1 + PFN_UP(perm_trampoline_end - perm_trampoline_start))
                         : 0x100);
           i++ )
         share_xen_page_with_guest(mfn_to_page(_mfn(i)), dom_io, SHARE_rw);
diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c
index 4dd4c4161c..b255242561 100644
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -675,6 +675,42 @@ static int copy_bios_e820(struct e820entry *map, unsigned int limit)
     return n;
 }
 
+extern const s32 __trampoline_rel_start[], __trampoline_rel_stop[];
+extern const s32 __trampoline32_rel_start[], __trampoline32_rel_stop[];
+
+static void __init relocate_trampoline(unsigned long phys)
+{
+    const s32 *trampoline_ptr;
+    uint32_t tramp32_delta = 0;
+
+    /* Apply relocations to trampoline. */
+    for ( trampoline_ptr = __trampoline_rel_start;
+          trampoline_ptr < __trampoline_rel_stop;
+          ++trampoline_ptr )
+        *(u32 *)(*trampoline_ptr + (long)trampoline_ptr) += phys;
+
+    tramp32_delta = phys;
+    if (!efi_enabled(EFI_LOADER)) {
+        /*
+         * The non-EFI boot code uses the 32-bit trampoline in place
+         * so will have relocated it to the physical address of
+         * perm_trampoline_start already. Undo that as it needs to
+         * run from low memory for AP startup, because the Xen
+         * physical address range won't be mapped.
+         */
+        tramp32_delta -= trampoline_xen_phys_start;
+        tramp32_delta -= (unsigned long)(perm_trampoline_start - __XEN_VIRT_START);
+    }
+    for ( trampoline_ptr = __trampoline32_rel_start;
+          trampoline_ptr < __trampoline32_rel_stop;
+          ++trampoline_ptr )
+        *(u32 *)(*trampoline_ptr + (long)trampoline_ptr) += tramp32_delta;
+    trampoline_xen_phys_start = xen_phys_start;
+
+    memcpy(trampsym(perm_trampoline_start), perm_trampoline_start,
+           perm_trampoline_end - perm_trampoline_start);
+}
+
 void __init noreturn __start_xen(unsigned long mbi_p)
 {
     char *memmap_type = NULL;
@@ -1047,7 +1083,6 @@ void __init noreturn __start_xen(unsigned long mbi_p)
             /* Select relocation address. */
             e = end - reloc_size;
             xen_phys_start = e;
-            bootsym(trampoline_xen_phys_start) = e;
 
             /*
              * Perform relocation to new physical address.
@@ -1479,6 +1514,8 @@ void __init noreturn __start_xen(unsigned long mbi_p)
     else
         end_boot_allocator();
 
+    relocate_trampoline(trampoline_phys);
+
     system_state = SYS_STATE_boot;
     /*
      * No calls involving ACPI code should go between the setting of
@@ -1838,8 +1875,8 @@ int __hwdom_init xen_in_range(unsigned long mfn)
     if ( !xen_regions[0].s )
     {
         /* S3 resume code (and other real mode trampoline code) */
-        xen_regions[region_s3].s = bootsym_phys(boot_trampoline_start);
-        xen_regions[region_s3].e = bootsym_phys(boot_trampoline_end);
+        xen_regions[region_s3].s = trampsym_phys(perm_trampoline_start);
+        xen_regions[region_s3].e = trampsym_phys(perm_trampoline_end);
 
         /*
          * This needs to remain in sync with the uses of the same symbols in
diff --git a/xen/arch/x86/smpboot.c b/xen/arch/x86/smpboot.c
index 7e76cc3d68..02d97a1aa3 100644
--- a/xen/arch/x86/smpboot.c
+++ b/xen/arch/x86/smpboot.c
@@ -48,7 +48,7 @@
 #include <mach_wakecpu.h>
 #include <smpboot_hooks.h>
 
-#define setup_trampoline()    (bootsym_phys(trampoline_realmode_entry))
+#define setup_trampoline()    (trampsym_phys(trampoline_realmode_entry))
 
 unsigned long __read_mostly trampoline_phys;
 
@@ -600,7 +600,7 @@ static int do_boot_cpu(int apicid, int cpu)
         {
             boot_error = 1;
             smp_mb();
-            if ( bootsym(trampoline_cpu_started) == 0xA5 )
+            if ( trampsym(trampoline_cpu_started) == 0xA5 )
                 /* trampoline started but...? */
                 printk("Stuck ??\n");
             else
@@ -616,7 +616,7 @@ static int do_boot_cpu(int apicid, int cpu)
     }
 
     /* mark "stuck" area as not stuck */
-    bootsym(trampoline_cpu_started) = 0;
+    trampsym(trampoline_cpu_started) = 0;
     smp_mb();
 
     smpboot_restore_warm_reset_vector();
diff --git a/xen/arch/x86/tboot.c b/xen/arch/x86/tboot.c
index 9e3d9c4c69..006f0678a6 100644
--- a/xen/arch/x86/tboot.c
+++ b/xen/arch/x86/tboot.c
@@ -369,9 +369,9 @@ void tboot_shutdown(uint32_t shutdown_type)
          */
         g_tboot_shared->num_mac_regions = 3;
         /* S3 resume code (and other real mode trampoline code) */
-        g_tboot_shared->mac_regions[0].start = bootsym_phys(boot_trampoline_start);
-        g_tboot_shared->mac_regions[0].size = bootsym_phys(boot_trampoline_end) -
-                                              bootsym_phys(boot_trampoline_start);
+        g_tboot_shared->mac_regions[0].start = trampsym_phys(perm_trampoline_start);
+        g_tboot_shared->mac_regions[0].size = trampsym_phys(perm_trampoline_end) -
+                                              trampsym_phys(perm_trampoline_start);
         /* hypervisor .text + .rodata */
         g_tboot_shared->mac_regions[1].start = (uint64_t)__pa(&_stext);
         g_tboot_shared->mac_regions[1].size = __pa(&__2M_rodata_end) -
diff --git a/xen/arch/x86/x86_64/mm.c b/xen/arch/x86/x86_64/mm.c
index ffe8ba2086..dbbbc64beb 100644
--- a/xen/arch/x86/x86_64/mm.c
+++ b/xen/arch/x86/x86_64/mm.c
@@ -697,7 +697,7 @@ void __init zap_low_mappings(void)
 
     /* Replace with mapping of the boot trampoline only. */
     map_pages_to_xen(trampoline_phys, maddr_to_mfn(trampoline_phys),
-                     PFN_UP(boot_trampoline_end - boot_trampoline_start),
+                     PFN_UP(perm_trampoline_end - perm_trampoline_start),
                      __PAGE_HYPERVISOR);
 }
 
diff --git a/xen/include/asm-x86/acpi.h b/xen/include/asm-x86/acpi.h
index c138def1bd..dffe02a363 100644
--- a/xen/include/asm-x86/acpi.h
+++ b/xen/include/asm-x86/acpi.h
@@ -110,7 +110,7 @@ extern int acpi_scan_nodes(u64 start, u64 end);
 #ifdef CONFIG_ACPI_SLEEP
 
 extern struct acpi_sleep_info acpi_sinfo;
-#define acpi_video_flags bootsym(video_flags)
+#define acpi_video_flags trampsym(video_flags)
 struct xenpf_enter_acpi_sleep;
 extern int acpi_enter_sleep(struct xenpf_enter_acpi_sleep *sleep);
 extern int acpi_enter_state(u32 state);
diff --git a/xen/include/asm-x86/config.h b/xen/include/asm-x86/config.h
index 9b7ed50825..dbd7cb255a 100644
--- a/xen/include/asm-x86/config.h
+++ b/xen/include/asm-x86/config.h
@@ -90,12 +90,12 @@
 
 #ifndef __ASSEMBLY__
 extern unsigned long trampoline_phys;
-#define bootsym_phys(sym)                                 \
-    (((unsigned long)&(sym)-(unsigned long)&boot_trampoline_start)+trampoline_phys)
-#define bootsym(sym)                                      \
+#define trampsym_phys(sym)                                 \
+    (((unsigned long)&(sym)-(unsigned long)&perm_trampoline_start)+trampoline_phys)
+#define trampsym(sym)                                      \
     (*RELOC_HIDE((typeof(&(sym)))__va(__pa(&(sym))),      \
-                 trampoline_phys-__pa(boot_trampoline_start)))
-extern char boot_trampoline_start[], boot_trampoline_end[];
+                 trampoline_phys-__pa(perm_trampoline_start)))
+extern char perm_trampoline_start[], perm_trampoline_end[];
 extern char trampoline_realmode_entry[];
 extern unsigned int trampoline_xen_phys_start;
 extern unsigned char trampoline_cpu_started;
-- 
2.17.2


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^ permalink raw reply related	[flat|nested] 18+ messages in thread

* [Xen-devel] [RFC PATCH v2 7/7] x86/boot: Do not use trampoline for no-real-mode boot paths
@ 2019-05-01 19:39   ` David Woodhouse
  0 siblings, 0 replies; 18+ messages in thread
From: David Woodhouse @ 2019-05-01 19:39 UTC (permalink / raw)
  To: xen-devel

From: David Woodhouse <dwmw@amazon.co.uk>

Where booted from EFI or with no-real-mode, there is no need to stomp
on low memory with the 16-boot code. Instead, just go straight to
trampoline_protmode_entry() at its physical location within the Xen
image.

For now, the boot code (including the EFI loader path) still determines
what the trampoline_phys address should be. The trampoline is actually
relocated for that address and copied into low memory, from a
relocate_trampoline() call made from __start_xen().

For subsequent AP startup and wakeup, the 32-bit trampoline can't
trivially be used in-place as that region isn't mapped. So copy it
down to low memory too, having relocated it (again) to work from
there.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
---
 xen/arch/x86/acpi/power.c      |  6 +--
 xen/arch/x86/boot/head.S       | 67 ++++++++++++++++------------------
 xen/arch/x86/boot/trampoline.S | 30 +++++++++++----
 xen/arch/x86/cpu/common.c      |  2 +-
 xen/arch/x86/cpu/intel.c       |  2 +-
 xen/arch/x86/efi/efi-boot.h    | 31 ++--------------
 xen/arch/x86/mm.c              |  2 +-
 xen/arch/x86/setup.c           | 43 ++++++++++++++++++++--
 xen/arch/x86/smpboot.c         |  6 +--
 xen/arch/x86/tboot.c           |  6 +--
 xen/arch/x86/x86_64/mm.c       |  2 +-
 xen/include/asm-x86/acpi.h     |  2 +-
 xen/include/asm-x86/config.h   | 10 ++---
 13 files changed, 117 insertions(+), 92 deletions(-)

diff --git a/xen/arch/x86/acpi/power.c b/xen/arch/x86/acpi/power.c
index a704c7c340..a1ce8acb21 100644
--- a/xen/arch/x86/acpi/power.c
+++ b/xen/arch/x86/acpi/power.c
@@ -152,9 +152,9 @@ static void acpi_sleep_prepare(u32 state)
         return;
 
     if ( acpi_sinfo.vector_width == 32 )
-        *(uint32_t *)wakeup_vector_va = bootsym_phys(wakeup_start);
+        *(uint32_t *)wakeup_vector_va = trampsym_phys(wakeup_start);
     else
-        *(uint64_t *)wakeup_vector_va = bootsym_phys(wakeup_start);
+        *(uint64_t *)wakeup_vector_va = trampsym_phys(wakeup_start);
 }
 
 static void acpi_sleep_post(u32 state) {}
@@ -388,7 +388,7 @@ static void tboot_sleep(u8 sleep_state)
     g_tboot_shared->acpi_sinfo.wakeup_vector = acpi_sinfo.wakeup_vector;
     g_tboot_shared->acpi_sinfo.vector_width = acpi_sinfo.vector_width;
     g_tboot_shared->acpi_sinfo.kernel_s3_resume_vector =
-                                              bootsym_phys(wakeup_start);
+                                              trampsym_phys(wakeup_start);
 
     switch ( sleep_state )
     {
diff --git a/xen/arch/x86/boot/head.S b/xen/arch/x86/boot/head.S
index 7d6c8d3292..c23eeb3aa4 100644
--- a/xen/arch/x86/boot/head.S
+++ b/xen/arch/x86/boot/head.S
@@ -696,16 +696,23 @@ trampoline_setup:
         lea     __PAGE_HYPERVISOR+sym_esi(l1_identmap),%edi
         mov     %edi,sym_fs(l2_bootmap)
 
-        /* Apply relocations to bootstrap trampoline. */
-        mov     sym_fs(trampoline_phys),%edx
-        mov     $sym_offs(__trampoline_rel_start),%edi
-1:
-        mov     %fs:(%edi),%eax
-        add     %edx,%fs:(%edi,%eax)
-        add     $4,%edi
-        cmp     $sym_offs(__trampoline_rel_stop),%edi
-        jb      1b
+        /* Do not parse command line on EFI platform here. */
+        cmpb    $0,sym_fs(efi_platform)
+        jnz     1f
 
+        /* Bail if there is no command line to parse. */
+        mov     sym_fs(multiboot_ptr),%ebx
+        testl   $MBI_CMDLINE,MB_flags(%ebx)
+        jz      1f
+
+        lea     sym_esi(early_boot_opts),%eax
+        push    %eax
+        pushl   MB_cmdline(%ebx)
+        call    cmdline_parse_early
+
+1:
+        /* Apply relocations to 32-bit trampoline for execution in place. */
+        lea     sym_esi(perm_trampoline_start),%edx
         mov     $sym_offs(__trampoline32_rel_start),%edi
 1:
         mov     %fs:(%edi),%eax
@@ -714,6 +721,21 @@ trampoline_setup:
         cmp     $sym_offs(__trampoline32_rel_stop),%edi
         jb      1b
 
+        cmp     $0,sym_esi(skip_realmode)
+        jz      .Ldo_realmode
+
+        /* Go directly to trampoline_protmode_entry at its physical address */
+        lea     trampoline_protmode_entry-__XEN_VIRT_START(%esi),%eax
+        pushl   $BOOT_CS32
+        push    %eax
+
+        /* EBX == 0 indicates we are the BP (Boot Processor). */
+        xor     %ebx,%ebx
+        retl
+
+.Ldo_realmode:
+        /* Apply relocations to 16-bit boot code. */
+        mov     sym_fs(trampoline_phys),%edx
         mov     $sym_offs(__bootsym_rel_start),%edi
 1:
         mov     %fs:(%edi),%eax
@@ -743,35 +765,12 @@ trampoline_setup:
         cmp     $sym_offs(__bootdatasym_rel_stop),%edi
         jb      1b
 
-        /* Do not parse command line on EFI platform here. */
-        cmpb    $0,sym_fs(efi_platform)
-        jnz     1f
-
-        /* Bail if there is no command line to parse. */
-        mov     sym_fs(multiboot_ptr),%ebx
-        testl   $MBI_CMDLINE,MB_flags(%ebx)
-        jz      1f
-
-        lea     sym_esi(early_boot_opts),%eax
-        push    %eax
-        pushl   MB_cmdline(%ebx)
-        call    cmdline_parse_early
-
-1:
         /* Switch to low-memory stack which lives at the end of trampoline region. */
         mov     sym_fs(trampoline_phys),%edi
         lea     TRAMPOLINE_SPACE+TRAMPOLINE_STACK_SPACE(%edi),%esp
-        cmpb    $0, sym_fs(skip_realmode)
-        jz      1f
-        /* If no-real-mode, jump straight to trampoline_protmode_entry */
-        lea     trampoline_protmode_entry-boot_trampoline_start(%edi),%eax
-        /* EBX == 0 indicates we are the BP (Boot Processor). */
-        xor     %ebx,%ebx
-        jmp     2f
-1:
+
         /* Go via 16-bit code in trampoline_boot_cpu_entry */
         lea     trampoline_boot_cpu_entry-boot_trampoline_start(%edi),%eax
-2:
         pushl   $BOOT_CS32
         push    %eax
 
@@ -794,8 +793,6 @@ cmdline_parse_early:
 reloc:
 #include "reloc.S"
 
-ENTRY(boot_trampoline_start)
 #include "trampoline.S"
-ENTRY(boot_trampoline_end)
 
 #include "x86_64.S"
diff --git a/xen/arch/x86/boot/trampoline.S b/xen/arch/x86/boot/trampoline.S
index fdfee2edb1..1ce815e0da 100644
--- a/xen/arch/x86/boot/trampoline.S
+++ b/xen/arch/x86/boot/trampoline.S
@@ -60,7 +60,7 @@ GLOBAL(bootdata_start)
         .popsection
 
 #undef trampsym
-#define trampsym(s) ((s)-boot_trampoline_start)
+#define trampsym(s) ((s)-perm_trampoline_start)
 
 #define trampsym_rel(sym, off, opnd...)    \
         trampsym(sym),##opnd;              \
@@ -70,7 +70,7 @@ GLOBAL(bootdata_start)
         .popsection
 
 #undef tramp32sym
-#define tramp32sym(s) ((s)-boot_trampoline_start)
+#define tramp32sym(s) ((s)-perm_trampoline_start)
 
 #define tramp32sym_rel(sym, off, opnd...)  \
         tramp32sym(sym),##opnd;            \
@@ -83,6 +83,7 @@ GLOBAL(bootdata_start)
 
         .code16
 
+ENTRY(perm_trampoline_start)
 GLOBAL(trampoline_realmode_entry)
         mov     %cs,%ax
         mov     %ax,%ds
@@ -90,7 +91,7 @@ GLOBAL(trampoline_realmode_entry)
         cld
         cli
         lidt    trampsym(idt_48)
-        lgdt    trampsym(gdt_48)
+        lgdtl   trampsym(gdt_48)
         mov     $1,%bl                    # EBX != 0 indicates we are an AP
         xor     %ax, %ax
         inc     %ax
@@ -230,11 +231,23 @@ start64:
 
 /* The first page of trampoline is permanent, the rest boot-time only. */
 /* Reuse the boot trampoline on the 1st trampoline page as stack for wakeup. */
-        .equ    wakeup_stack, boot_trampoline_start + PAGE_SIZE
+        .equ    wakeup_stack, perm_trampoline_start + PAGE_SIZE
         .global wakeup_stack
 
+ENTRY(perm_trampoline_end)
+
 /* From here on early boot only. */
 
+ENTRY(boot_trampoline_start)
+
+        .word   0
+boot16_idt:
+        .word   0, 0, 0 # base = limit = 0
+        .word   0
+boot16_gdt:
+        .word   7*8-1
+        .long   tramp32sym_rel(trampoline_gdt,4)
+
         .code32
 trampoline_boot_cpu_entry:
         /* Load pseudo-real-mode segments. */
@@ -298,8 +311,8 @@ trampoline_boot_cpu_entry:
         cli
 
         /* Reset GDT and IDT. Some BIOSes clobber GDTR. */
-        lidt    bootsym(idt_48)
-        lgdt    bootsym(gdt_48)
+        lidt    bootsym(boot16_idt) # XXX
+        lgdtl   bootsym(boot16_gdt)
 
         /* Enter protected mode, and flush insn queue. */
         xor     %ax,%ax
@@ -337,7 +350,8 @@ trampoline_boot_cpu_entry:
         xor     %ebx,%ebx
 
         /* Jump to the common bootstrap entry point. */
-        jmp     trampoline_protmode_entry
+        mov     $tramp32sym_rel(trampoline_protmode_entry,4,%eax)
+        jmp     *%eax
 
 #include "video.h"
 
@@ -373,6 +387,8 @@ rm_idt: .word   256*4-1, 0, 0
 #include "video.S"
 #endif
 
+ENTRY(boot_trampoline_end)
+
         .pushsection .data.boot16, "aw", @progbits
 GLOBAL(bootdata_end)
         .popsection
diff --git a/xen/arch/x86/cpu/common.c b/xen/arch/x86/cpu/common.c
index 1d21ff9467..b268e010c5 100644
--- a/xen/arch/x86/cpu/common.c
+++ b/xen/arch/x86/cpu/common.c
@@ -408,7 +408,7 @@ static void generic_identify(struct cpuinfo_x86 *c)
 		      &c->x86_capability[cpufeat_word(X86_FEATURE_LAHF_LM)],
 		      &c->x86_capability[cpufeat_word(X86_FEATURE_SYSCALL)]);
 	if (c == &boot_cpu_data)
-		bootsym(cpuid_ext_features) =
+		trampsym(cpuid_ext_features) =
 			c->x86_capability[cpufeat_word(X86_FEATURE_NX)];
 
 	if (c->extended_cpuid_level >= 0x80000004)
diff --git a/xen/arch/x86/cpu/intel.c b/xen/arch/x86/cpu/intel.c
index 8e23ed6379..e7f794a601 100644
--- a/xen/arch/x86/cpu/intel.c
+++ b/xen/arch/x86/cpu/intel.c
@@ -240,7 +240,7 @@ static void early_init_intel(struct cpuinfo_x86 *c)
 				 MSR_IA32_MISC_ENABLE_XD_DISABLE);
 	if (disable) {
 		wrmsrl(MSR_IA32_MISC_ENABLE, misc_enable & ~disable);
-		bootsym(trampoline_misc_enable_off) |= disable;
+		trampsym(trampoline_misc_enable_off) |= disable;
 	}
 
 	if (disable & MSR_IA32_MISC_ENABLE_LIMIT_CPUID)
diff --git a/xen/arch/x86/efi/efi-boot.h b/xen/arch/x86/efi/efi-boot.h
index f6f435a4c5..ecec334d60 100644
--- a/xen/arch/x86/efi/efi-boot.h
+++ b/xen/arch/x86/efi/efi-boot.h
@@ -98,29 +98,6 @@ static void __init efi_arch_relocate_image(unsigned long delta)
     }
 }
 
-extern const s32 __trampoline_rel_start[], __trampoline_rel_stop[];
-extern const s32 __trampoline32_rel_start[], __trampoline32_rel_stop[];
-
-static void __init relocate_trampoline(unsigned long phys)
-{
-    const s32 *trampoline_ptr;
-
-    trampoline_phys = phys;
-
-    if ( !efi_enabled(EFI_LOADER) )
-        return;
-
-    /* Apply relocations to trampoline. */
-    for ( trampoline_ptr = __trampoline_rel_start;
-          trampoline_ptr < __trampoline_rel_stop;
-          ++trampoline_ptr )
-        *(u32 *)(*trampoline_ptr + (long)trampoline_ptr) += phys;
-    for ( trampoline_ptr = __trampoline32_rel_start;
-          trampoline_ptr < __trampoline32_rel_stop;
-          ++trampoline_ptr )
-        *(u32 *)(*trampoline_ptr + (long)trampoline_ptr) += phys;
-}
-
 static void __init place_string(u32 *addr, const char *s)
 {
     char *alloc = NULL;
@@ -223,7 +200,7 @@ static void __init efi_arch_pre_exit_boot(void)
     {
         if ( !cfg.addr )
             blexit(L"No memory for trampoline");
-        relocate_trampoline(cfg.addr);
+        trampoline_phys = cfg.addr;
     }
 }
 
@@ -232,7 +209,6 @@ static void __init noreturn efi_arch_post_exit_boot(void)
     u64 cr4 = XEN_MINIMAL_CR4 & ~X86_CR4_PGE, efer;
 
     efi_arch_relocate_image(__XEN_VIRT_START - xen_phys_start);
-    memcpy((void *)trampoline_phys, boot_trampoline_start, cfg.size);
 
     /* Set system registers and transfer control. */
     asm volatile("pushq $0\n\tpopfq");
@@ -565,14 +541,14 @@ static void __init efi_arch_memory_setup(void)
     cfg.addr = 0x100000;
 
     if ( efi_enabled(EFI_LOADER) )
-        cfg.size = boot_trampoline_end - boot_trampoline_start;
+        cfg.size = perm_trampoline_end - perm_trampoline_start;
     else
         cfg.size = TRAMPOLINE_SPACE + TRAMPOLINE_STACK_SPACE;
 
     status = efi_bs->AllocatePages(AllocateMaxAddress, EfiLoaderData,
                                    PFN_UP(cfg.size), &cfg.addr);
     if ( status == EFI_SUCCESS )
-        relocate_trampoline(cfg.addr);
+        trampoline_phys = cfg.addr;
     else
     {
         cfg.addr = 0;
@@ -664,7 +640,6 @@ static void __init efi_arch_load_addr_check(EFI_LOADED_IMAGE *loaded_image)
         blexit(L"Xen must be loaded below 4Gb.");
     if ( xen_phys_start & ((1 << L2_PAGETABLE_SHIFT) - 1) )
         blexit(L"Xen must be loaded at a 2Mb boundary.");
-    trampoline_xen_phys_start = xen_phys_start;
 }
 
 static bool __init efi_arch_use_config_file(EFI_SYSTEM_TABLE *SystemTable)
diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
index 7a2e188916..17a55b4b8a 100644
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -314,7 +314,7 @@ void __init arch_init_memory(void)
      */
     BUG_ON(pvh_boot && trampoline_phys != 0x1000);
     for ( i = 0;
-          i < (pvh_boot ? (1 + PFN_UP(boot_trampoline_end - boot_trampoline_start))
+          i < (pvh_boot ? (1 + PFN_UP(perm_trampoline_end - perm_trampoline_start))
                         : 0x100);
           i++ )
         share_xen_page_with_guest(mfn_to_page(_mfn(i)), dom_io, SHARE_rw);
diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c
index 4dd4c4161c..b255242561 100644
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -675,6 +675,42 @@ static int copy_bios_e820(struct e820entry *map, unsigned int limit)
     return n;
 }
 
+extern const s32 __trampoline_rel_start[], __trampoline_rel_stop[];
+extern const s32 __trampoline32_rel_start[], __trampoline32_rel_stop[];
+
+static void __init relocate_trampoline(unsigned long phys)
+{
+    const s32 *trampoline_ptr;
+    uint32_t tramp32_delta = 0;
+
+    /* Apply relocations to trampoline. */
+    for ( trampoline_ptr = __trampoline_rel_start;
+          trampoline_ptr < __trampoline_rel_stop;
+          ++trampoline_ptr )
+        *(u32 *)(*trampoline_ptr + (long)trampoline_ptr) += phys;
+
+    tramp32_delta = phys;
+    if (!efi_enabled(EFI_LOADER)) {
+        /*
+         * The non-EFI boot code uses the 32-bit trampoline in place
+         * so will have relocated it to the physical address of
+         * perm_trampoline_start already. Undo that as it needs to
+         * run from low memory for AP startup, because the Xen
+         * physical address range won't be mapped.
+         */
+        tramp32_delta -= trampoline_xen_phys_start;
+        tramp32_delta -= (unsigned long)(perm_trampoline_start - __XEN_VIRT_START);
+    }
+    for ( trampoline_ptr = __trampoline32_rel_start;
+          trampoline_ptr < __trampoline32_rel_stop;
+          ++trampoline_ptr )
+        *(u32 *)(*trampoline_ptr + (long)trampoline_ptr) += tramp32_delta;
+    trampoline_xen_phys_start = xen_phys_start;
+
+    memcpy(trampsym(perm_trampoline_start), perm_trampoline_start,
+           perm_trampoline_end - perm_trampoline_start);
+}
+
 void __init noreturn __start_xen(unsigned long mbi_p)
 {
     char *memmap_type = NULL;
@@ -1047,7 +1083,6 @@ void __init noreturn __start_xen(unsigned long mbi_p)
             /* Select relocation address. */
             e = end - reloc_size;
             xen_phys_start = e;
-            bootsym(trampoline_xen_phys_start) = e;
 
             /*
              * Perform relocation to new physical address.
@@ -1479,6 +1514,8 @@ void __init noreturn __start_xen(unsigned long mbi_p)
     else
         end_boot_allocator();
 
+    relocate_trampoline(trampoline_phys);
+
     system_state = SYS_STATE_boot;
     /*
      * No calls involving ACPI code should go between the setting of
@@ -1838,8 +1875,8 @@ int __hwdom_init xen_in_range(unsigned long mfn)
     if ( !xen_regions[0].s )
     {
         /* S3 resume code (and other real mode trampoline code) */
-        xen_regions[region_s3].s = bootsym_phys(boot_trampoline_start);
-        xen_regions[region_s3].e = bootsym_phys(boot_trampoline_end);
+        xen_regions[region_s3].s = trampsym_phys(perm_trampoline_start);
+        xen_regions[region_s3].e = trampsym_phys(perm_trampoline_end);
 
         /*
          * This needs to remain in sync with the uses of the same symbols in
diff --git a/xen/arch/x86/smpboot.c b/xen/arch/x86/smpboot.c
index 7e76cc3d68..02d97a1aa3 100644
--- a/xen/arch/x86/smpboot.c
+++ b/xen/arch/x86/smpboot.c
@@ -48,7 +48,7 @@
 #include <mach_wakecpu.h>
 #include <smpboot_hooks.h>
 
-#define setup_trampoline()    (bootsym_phys(trampoline_realmode_entry))
+#define setup_trampoline()    (trampsym_phys(trampoline_realmode_entry))
 
 unsigned long __read_mostly trampoline_phys;
 
@@ -600,7 +600,7 @@ static int do_boot_cpu(int apicid, int cpu)
         {
             boot_error = 1;
             smp_mb();
-            if ( bootsym(trampoline_cpu_started) == 0xA5 )
+            if ( trampsym(trampoline_cpu_started) == 0xA5 )
                 /* trampoline started but...? */
                 printk("Stuck ??\n");
             else
@@ -616,7 +616,7 @@ static int do_boot_cpu(int apicid, int cpu)
     }
 
     /* mark "stuck" area as not stuck */
-    bootsym(trampoline_cpu_started) = 0;
+    trampsym(trampoline_cpu_started) = 0;
     smp_mb();
 
     smpboot_restore_warm_reset_vector();
diff --git a/xen/arch/x86/tboot.c b/xen/arch/x86/tboot.c
index 9e3d9c4c69..006f0678a6 100644
--- a/xen/arch/x86/tboot.c
+++ b/xen/arch/x86/tboot.c
@@ -369,9 +369,9 @@ void tboot_shutdown(uint32_t shutdown_type)
          */
         g_tboot_shared->num_mac_regions = 3;
         /* S3 resume code (and other real mode trampoline code) */
-        g_tboot_shared->mac_regions[0].start = bootsym_phys(boot_trampoline_start);
-        g_tboot_shared->mac_regions[0].size = bootsym_phys(boot_trampoline_end) -
-                                              bootsym_phys(boot_trampoline_start);
+        g_tboot_shared->mac_regions[0].start = trampsym_phys(perm_trampoline_start);
+        g_tboot_shared->mac_regions[0].size = trampsym_phys(perm_trampoline_end) -
+                                              trampsym_phys(perm_trampoline_start);
         /* hypervisor .text + .rodata */
         g_tboot_shared->mac_regions[1].start = (uint64_t)__pa(&_stext);
         g_tboot_shared->mac_regions[1].size = __pa(&__2M_rodata_end) -
diff --git a/xen/arch/x86/x86_64/mm.c b/xen/arch/x86/x86_64/mm.c
index ffe8ba2086..dbbbc64beb 100644
--- a/xen/arch/x86/x86_64/mm.c
+++ b/xen/arch/x86/x86_64/mm.c
@@ -697,7 +697,7 @@ void __init zap_low_mappings(void)
 
     /* Replace with mapping of the boot trampoline only. */
     map_pages_to_xen(trampoline_phys, maddr_to_mfn(trampoline_phys),
-                     PFN_UP(boot_trampoline_end - boot_trampoline_start),
+                     PFN_UP(perm_trampoline_end - perm_trampoline_start),
                      __PAGE_HYPERVISOR);
 }
 
diff --git a/xen/include/asm-x86/acpi.h b/xen/include/asm-x86/acpi.h
index c138def1bd..dffe02a363 100644
--- a/xen/include/asm-x86/acpi.h
+++ b/xen/include/asm-x86/acpi.h
@@ -110,7 +110,7 @@ extern int acpi_scan_nodes(u64 start, u64 end);
 #ifdef CONFIG_ACPI_SLEEP
 
 extern struct acpi_sleep_info acpi_sinfo;
-#define acpi_video_flags bootsym(video_flags)
+#define acpi_video_flags trampsym(video_flags)
 struct xenpf_enter_acpi_sleep;
 extern int acpi_enter_sleep(struct xenpf_enter_acpi_sleep *sleep);
 extern int acpi_enter_state(u32 state);
diff --git a/xen/include/asm-x86/config.h b/xen/include/asm-x86/config.h
index 9b7ed50825..dbd7cb255a 100644
--- a/xen/include/asm-x86/config.h
+++ b/xen/include/asm-x86/config.h
@@ -90,12 +90,12 @@
 
 #ifndef __ASSEMBLY__
 extern unsigned long trampoline_phys;
-#define bootsym_phys(sym)                                 \
-    (((unsigned long)&(sym)-(unsigned long)&boot_trampoline_start)+trampoline_phys)
-#define bootsym(sym)                                      \
+#define trampsym_phys(sym)                                 \
+    (((unsigned long)&(sym)-(unsigned long)&perm_trampoline_start)+trampoline_phys)
+#define trampsym(sym)                                      \
     (*RELOC_HIDE((typeof(&(sym)))__va(__pa(&(sym))),      \
-                 trampoline_phys-__pa(boot_trampoline_start)))
-extern char boot_trampoline_start[], boot_trampoline_end[];
+                 trampoline_phys-__pa(perm_trampoline_start)))
+extern char perm_trampoline_start[], perm_trampoline_end[];
 extern char trampoline_realmode_entry[];
 extern unsigned int trampoline_xen_phys_start;
 extern unsigned char trampoline_cpu_started;
-- 
2.17.2


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Xen-devel@lists.xenproject.org
https://lists.xenproject.org/mailman/listinfo/xen-devel

^ permalink raw reply related	[flat|nested] 18+ messages in thread

* Re: [RFC PATCH v2 0/7] Clean up x86_64 boot code
@ 2019-05-01 19:46   ` David Woodhouse
  0 siblings, 0 replies; 18+ messages in thread
From: David Woodhouse @ 2019-05-01 19:46 UTC (permalink / raw)
  To: xen-devel


[-- Attachment #1.1: Type: text/plain, Size: 201 bytes --]

Argh, that's the first version again. Sorry. The fixed version is in 
http://git.infradead.org/users/dwmw2/xen.git/shortlog/refs/heads/bootcleanup
but I won't post the whole series again right now.

[-- Attachment #1.2: smime.p7s --]
[-- Type: application/x-pkcs7-signature, Size: 5174 bytes --]

[-- Attachment #2: Type: text/plain, Size: 157 bytes --]

_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xenproject.org
https://lists.xenproject.org/mailman/listinfo/xen-devel

^ permalink raw reply	[flat|nested] 18+ messages in thread

* Re: [Xen-devel] [RFC PATCH v2 0/7] Clean up x86_64 boot code
@ 2019-05-01 19:46   ` David Woodhouse
  0 siblings, 0 replies; 18+ messages in thread
From: David Woodhouse @ 2019-05-01 19:46 UTC (permalink / raw)
  To: xen-devel


[-- Attachment #1.1: Type: text/plain, Size: 201 bytes --]

Argh, that's the first version again. Sorry. The fixed version is in 
http://git.infradead.org/users/dwmw2/xen.git/shortlog/refs/heads/bootcleanup
but I won't post the whole series again right now.

[-- Attachment #1.2: smime.p7s --]
[-- Type: application/x-pkcs7-signature, Size: 5174 bytes --]

[-- Attachment #2: Type: text/plain, Size: 157 bytes --]

_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xenproject.org
https://lists.xenproject.org/mailman/listinfo/xen-devel

^ permalink raw reply	[flat|nested] 18+ messages in thread

end of thread, other threads:[~2019-05-01 19:46 UTC | newest]

Thread overview: 18+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-05-01 19:39 [RFC PATCH v2 0/7] Clean up x86_64 boot code David Woodhouse
2019-05-01 19:39 ` [Xen-devel] " David Woodhouse
2019-05-01 19:39 ` [RFC PATCH v2 1/7] x86/wakeup: Stop using %fs for lidt/lgdt David Woodhouse
2019-05-01 19:39   ` [Xen-devel] " David Woodhouse
2019-05-01 19:39 ` [RFC PATCH v2 2/7] x86/boot: Remove gratuitous call back into low-memory code David Woodhouse
2019-05-01 19:39   ` [Xen-devel] " David Woodhouse
2019-05-01 19:39 ` [RFC PATCH v2 3/7] x86/boot: Only jump into low trampoline code for real-mode boot David Woodhouse
2019-05-01 19:39   ` [Xen-devel] " David Woodhouse
2019-05-01 19:39 ` [RFC PATCH v2 4/7] x86/boot: Split bootsym() into four types of relocations David Woodhouse
2019-05-01 19:39   ` [Xen-devel] " David Woodhouse
2019-05-01 19:39 ` [RFC PATCH v2 5/7] x86/boot: Rename trampoline_{start, end} to boot_trampoline_{start, end} David Woodhouse
2019-05-01 19:39   ` [Xen-devel] " David Woodhouse
2019-05-01 19:39 ` [RFC PATCH v2 6/7] x86/boot: Copy 16-bit boot variables back up to Xen image David Woodhouse
2019-05-01 19:39   ` [Xen-devel] " David Woodhouse
2019-05-01 19:39 ` [RFC PATCH v2 7/7] x86/boot: Do not use trampoline for no-real-mode boot paths David Woodhouse
2019-05-01 19:39   ` [Xen-devel] " David Woodhouse
2019-05-01 19:46 ` [RFC PATCH v2 0/7] Clean up x86_64 boot code David Woodhouse
2019-05-01 19:46   ` [Xen-devel] " David Woodhouse

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