* [PATCH v4 0/3] arm64: EFI stub isolation
@ 2015-10-08 19:02 ` Ard Biesheuvel
0 siblings, 0 replies; 46+ messages in thread
From: Ard Biesheuvel @ 2015-10-08 19:02 UTC (permalink / raw)
To: linux-efi-u79uwXL29TY76Z2rM5mHXA,
linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r,
matt.fleming-ral2JQCrhuEAvxtiuMwx3w, mark.rutland-5wv7dgnIgG8,
catalin.marinas-5wv7dgnIgG8, will.deacon-5wv7dgnIgG8,
leif.lindholm-QSEj5FYQhm4dnm+yROfE0A
Cc: ryabinin.a.a-Re5JQEeQqe8AvxtiuMwx3w, Ard Biesheuvel
We need to ensure that the EFI stub only uses parts of the kernel proper
that are safe to use when the kernel virtual mapping is not active yet.
So move all C code dependencies to the libstub, which is built with all
instrumentation (gcov, kasan) disabled, and do a verification pass to
ensure that no absolute relocations are used.
On the arm64 side, annotate all the stub's dependencies as safe for PI
(position independent
@Matt: if you are OK with these, may we please have your ack on patches #1 and
#2 so that Catalin can pick up the series? Thanks.
Changes since v3:
- expose strcmp() which we will need for EFI stub patches that may enter
mainline via another subsystem tree
- rebase onto arm64/for-next/core
Changes since v2:
- fold patch that removes the linux_banner from the /chosen node UEFI specific
properties; if we are all in agreement that we can get rid of it (which I
think we are), it makes sense to do it straight away, and not export
linux_banner into the stub now only to remove it later
- tweaked libstub Makefile rules for easier ARM reuse
- rebase onto v4.3-rc4
Changes since v1:
- add .size and .type directives to correctly annotate the __pi_xxx aliases
as functions of the correct size
- add '#ifndef __HAVE_ARCH_STRSTR' around strstr() definition
- added linux-efi/Matt to cc
Ard Biesheuvel (3):
arm64/efi: remove /chosen/linux,uefi-stub-kern-ver DT property
arm64: use ENDPIPROC() to annotate position independent assembler
routines
arm64/efi: isolate EFI stub from the kernel proper
Documentation/arm/uefi.txt | 2 -
arch/arm64/include/asm/assembler.h | 11 ++++
arch/arm64/kernel/Makefile | 12 ++++-
arch/arm64/kernel/efi-entry.S | 10 ++--
arch/arm64/kernel/head.S | 14 ++---
arch/arm64/kernel/image.h | 27 ++++++++++
arch/arm64/lib/memchr.S | 2 +-
arch/arm64/lib/memcmp.S | 2 +-
arch/arm64/lib/memcpy.S | 2 +-
arch/arm64/lib/memmove.S | 2 +-
arch/arm64/lib/memset.S | 2 +-
arch/arm64/lib/strcmp.S | 2 +-
arch/arm64/lib/strlen.S | 2 +-
arch/arm64/lib/strncmp.S | 2 +-
arch/arm64/mm/cache.S | 10 ++--
drivers/firmware/efi/libstub/Makefile | 39 +++++++++++---
drivers/firmware/efi/libstub/fdt.c | 9 ----
drivers/firmware/efi/libstub/string.c | 57 ++++++++++++++++++++
18 files changed, 163 insertions(+), 44 deletions(-)
create mode 100644 drivers/firmware/efi/libstub/string.c
--
1.9.1
^ permalink raw reply [flat|nested] 46+ messages in thread
* [PATCH v4 0/3] arm64: EFI stub isolation
@ 2015-10-08 19:02 ` Ard Biesheuvel
0 siblings, 0 replies; 46+ messages in thread
From: Ard Biesheuvel @ 2015-10-08 19:02 UTC (permalink / raw)
To: linux-arm-kernel
We need to ensure that the EFI stub only uses parts of the kernel proper
that are safe to use when the kernel virtual mapping is not active yet.
So move all C code dependencies to the libstub, which is built with all
instrumentation (gcov, kasan) disabled, and do a verification pass to
ensure that no absolute relocations are used.
On the arm64 side, annotate all the stub's dependencies as safe for PI
(position independent
@Matt: if you are OK with these, may we please have your ack on patches #1 and
#2 so that Catalin can pick up the series? Thanks.
Changes since v3:
- expose strcmp() which we will need for EFI stub patches that may enter
mainline via another subsystem tree
- rebase onto arm64/for-next/core
Changes since v2:
- fold patch that removes the linux_banner from the /chosen node UEFI specific
properties; if we are all in agreement that we can get rid of it (which I
think we are), it makes sense to do it straight away, and not export
linux_banner into the stub now only to remove it later
- tweaked libstub Makefile rules for easier ARM reuse
- rebase onto v4.3-rc4
Changes since v1:
- add .size and .type directives to correctly annotate the __pi_xxx aliases
as functions of the correct size
- add '#ifndef __HAVE_ARCH_STRSTR' around strstr() definition
- added linux-efi/Matt to cc
Ard Biesheuvel (3):
arm64/efi: remove /chosen/linux,uefi-stub-kern-ver DT property
arm64: use ENDPIPROC() to annotate position independent assembler
routines
arm64/efi: isolate EFI stub from the kernel proper
Documentation/arm/uefi.txt | 2 -
arch/arm64/include/asm/assembler.h | 11 ++++
arch/arm64/kernel/Makefile | 12 ++++-
arch/arm64/kernel/efi-entry.S | 10 ++--
arch/arm64/kernel/head.S | 14 ++---
arch/arm64/kernel/image.h | 27 ++++++++++
arch/arm64/lib/memchr.S | 2 +-
arch/arm64/lib/memcmp.S | 2 +-
arch/arm64/lib/memcpy.S | 2 +-
arch/arm64/lib/memmove.S | 2 +-
arch/arm64/lib/memset.S | 2 +-
arch/arm64/lib/strcmp.S | 2 +-
arch/arm64/lib/strlen.S | 2 +-
arch/arm64/lib/strncmp.S | 2 +-
arch/arm64/mm/cache.S | 10 ++--
drivers/firmware/efi/libstub/Makefile | 39 +++++++++++---
drivers/firmware/efi/libstub/fdt.c | 9 ----
drivers/firmware/efi/libstub/string.c | 57 ++++++++++++++++++++
18 files changed, 163 insertions(+), 44 deletions(-)
create mode 100644 drivers/firmware/efi/libstub/string.c
--
1.9.1
^ permalink raw reply [flat|nested] 46+ messages in thread
* [PATCH v4 1/3] arm64/efi: remove /chosen/linux,uefi-stub-kern-ver DT property
2015-10-08 19:02 ` Ard Biesheuvel
@ 2015-10-08 19:02 ` Ard Biesheuvel
-1 siblings, 0 replies; 46+ messages in thread
From: Ard Biesheuvel @ 2015-10-08 19:02 UTC (permalink / raw)
To: linux-efi-u79uwXL29TY76Z2rM5mHXA,
linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r,
matt.fleming-ral2JQCrhuEAvxtiuMwx3w, mark.rutland-5wv7dgnIgG8,
catalin.marinas-5wv7dgnIgG8, will.deacon-5wv7dgnIgG8,
leif.lindholm-QSEj5FYQhm4dnm+yROfE0A
Cc: ryabinin.a.a-Re5JQEeQqe8AvxtiuMwx3w, Ard Biesheuvel
With the stub to kernel interface being promoted to a proper interface
so that other agents than the stub can boot the kernel proper in EFI
mode, we can remove the linux,uefi-stub-kern-ver field, considering
that its original purpose was to prevent this from happening in the
first place.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
---
Documentation/arm/uefi.txt | 2 --
drivers/firmware/efi/libstub/fdt.c | 9 ---------
2 files changed, 11 deletions(-)
diff --git a/Documentation/arm/uefi.txt b/Documentation/arm/uefi.txt
index d60030a1b909..7f1bed8872f3 100644
--- a/Documentation/arm/uefi.txt
+++ b/Documentation/arm/uefi.txt
@@ -58,7 +58,5 @@ linux,uefi-mmap-desc-size | 32-bit | Size in bytes of each entry in the UEFI
--------------------------------------------------------------------------------
linux,uefi-mmap-desc-ver | 32-bit | Version of the mmap descriptor format.
--------------------------------------------------------------------------------
-linux,uefi-stub-kern-ver | string | Copy of linux_banner from build.
---------------------------------------------------------------------------------
For verbose debug messages, specify 'uefi_debug' on the kernel command line.
diff --git a/drivers/firmware/efi/libstub/fdt.c b/drivers/firmware/efi/libstub/fdt.c
index ef5d764e2a27..b62e2f5dcab3 100644
--- a/drivers/firmware/efi/libstub/fdt.c
+++ b/drivers/firmware/efi/libstub/fdt.c
@@ -147,15 +147,6 @@ efi_status_t update_fdt(efi_system_table_t *sys_table, void *orig_fdt,
if (status)
goto fdt_set_fail;
- /*
- * Add kernel version banner so stub/kernel match can be
- * verified.
- */
- status = fdt_setprop_string(fdt, node, "linux,uefi-stub-kern-ver",
- linux_banner);
- if (status)
- goto fdt_set_fail;
-
return EFI_SUCCESS;
fdt_set_fail:
--
1.9.1
^ permalink raw reply related [flat|nested] 46+ messages in thread
* [PATCH v4 1/3] arm64/efi: remove /chosen/linux, uefi-stub-kern-ver DT property
@ 2015-10-08 19:02 ` Ard Biesheuvel
0 siblings, 0 replies; 46+ messages in thread
From: Ard Biesheuvel @ 2015-10-08 19:02 UTC (permalink / raw)
To: linux-arm-kernel
With the stub to kernel interface being promoted to a proper interface
so that other agents than the stub can boot the kernel proper in EFI
mode, we can remove the linux,uefi-stub-kern-ver field, considering
that its original purpose was to prevent this from happening in the
first place.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
Documentation/arm/uefi.txt | 2 --
drivers/firmware/efi/libstub/fdt.c | 9 ---------
2 files changed, 11 deletions(-)
diff --git a/Documentation/arm/uefi.txt b/Documentation/arm/uefi.txt
index d60030a1b909..7f1bed8872f3 100644
--- a/Documentation/arm/uefi.txt
+++ b/Documentation/arm/uefi.txt
@@ -58,7 +58,5 @@ linux,uefi-mmap-desc-size | 32-bit | Size in bytes of each entry in the UEFI
--------------------------------------------------------------------------------
linux,uefi-mmap-desc-ver | 32-bit | Version of the mmap descriptor format.
--------------------------------------------------------------------------------
-linux,uefi-stub-kern-ver | string | Copy of linux_banner from build.
---------------------------------------------------------------------------------
For verbose debug messages, specify 'uefi_debug' on the kernel command line.
diff --git a/drivers/firmware/efi/libstub/fdt.c b/drivers/firmware/efi/libstub/fdt.c
index ef5d764e2a27..b62e2f5dcab3 100644
--- a/drivers/firmware/efi/libstub/fdt.c
+++ b/drivers/firmware/efi/libstub/fdt.c
@@ -147,15 +147,6 @@ efi_status_t update_fdt(efi_system_table_t *sys_table, void *orig_fdt,
if (status)
goto fdt_set_fail;
- /*
- * Add kernel version banner so stub/kernel match can be
- * verified.
- */
- status = fdt_setprop_string(fdt, node, "linux,uefi-stub-kern-ver",
- linux_banner);
- if (status)
- goto fdt_set_fail;
-
return EFI_SUCCESS;
fdt_set_fail:
--
1.9.1
^ permalink raw reply related [flat|nested] 46+ messages in thread
* [PATCH v4 2/3] arm64: use ENDPIPROC() to annotate position independent assembler routines
2015-10-08 19:02 ` Ard Biesheuvel
@ 2015-10-08 19:02 ` Ard Biesheuvel
-1 siblings, 0 replies; 46+ messages in thread
From: Ard Biesheuvel @ 2015-10-08 19:02 UTC (permalink / raw)
To: linux-efi-u79uwXL29TY76Z2rM5mHXA,
linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r,
matt.fleming-ral2JQCrhuEAvxtiuMwx3w, mark.rutland-5wv7dgnIgG8,
catalin.marinas-5wv7dgnIgG8, will.deacon-5wv7dgnIgG8,
leif.lindholm-QSEj5FYQhm4dnm+yROfE0A
Cc: ryabinin.a.a-Re5JQEeQqe8AvxtiuMwx3w, Ard Biesheuvel
For more control over which functions are called with the MMU off or
with the UEFI 1:1 mapping active, annotate some assembler routines as
position independent. This is done by introducing ENDPIPROC(), which
replaces the ENDPROC() declaration of those routines.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
---
arch/arm64/include/asm/assembler.h | 11 +++++++++++
arch/arm64/lib/memchr.S | 2 +-
arch/arm64/lib/memcmp.S | 2 +-
arch/arm64/lib/memcpy.S | 2 +-
arch/arm64/lib/memmove.S | 2 +-
arch/arm64/lib/memset.S | 2 +-
arch/arm64/lib/strcmp.S | 2 +-
arch/arm64/lib/strlen.S | 2 +-
arch/arm64/lib/strncmp.S | 2 +-
arch/arm64/mm/cache.S | 10 +++++-----
10 files changed, 24 insertions(+), 13 deletions(-)
diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h
index b51f2cc22ca9..12eff928ef8b 100644
--- a/arch/arm64/include/asm/assembler.h
+++ b/arch/arm64/include/asm/assembler.h
@@ -193,4 +193,15 @@ lr .req x30 // link register
str \src, [\tmp, :lo12:\sym]
.endm
+/*
+ * Annotate a function as position independent, i.e., safe to be called before
+ * the kernel virtual mapping is activated.
+ */
+#define ENDPIPROC(x) \
+ .globl __pi_##x; \
+ .type __pi_##x, %function; \
+ .set __pi_##x, x; \
+ .size __pi_##x, . - x; \
+ ENDPROC(x)
+
#endif /* __ASM_ASSEMBLER_H */
diff --git a/arch/arm64/lib/memchr.S b/arch/arm64/lib/memchr.S
index 8636b7549163..4444c1d25f4b 100644
--- a/arch/arm64/lib/memchr.S
+++ b/arch/arm64/lib/memchr.S
@@ -41,4 +41,4 @@ ENTRY(memchr)
ret
2: mov x0, #0
ret
-ENDPROC(memchr)
+ENDPIPROC(memchr)
diff --git a/arch/arm64/lib/memcmp.S b/arch/arm64/lib/memcmp.S
index 6ea0776ba6de..ffbdec00327d 100644
--- a/arch/arm64/lib/memcmp.S
+++ b/arch/arm64/lib/memcmp.S
@@ -255,4 +255,4 @@ CPU_LE( rev data2, data2 )
.Lret0:
mov result, #0
ret
-ENDPROC(memcmp)
+ENDPIPROC(memcmp)
diff --git a/arch/arm64/lib/memcpy.S b/arch/arm64/lib/memcpy.S
index 173a1aace9bb..36a6a62cf263 100644
--- a/arch/arm64/lib/memcpy.S
+++ b/arch/arm64/lib/memcpy.S
@@ -71,4 +71,4 @@
ENTRY(memcpy)
#include "copy_template.S"
ret
-ENDPROC(memcpy)
+ENDPIPROC(memcpy)
diff --git a/arch/arm64/lib/memmove.S b/arch/arm64/lib/memmove.S
index 57b19ea2dad4..68e2f2035e23 100644
--- a/arch/arm64/lib/memmove.S
+++ b/arch/arm64/lib/memmove.S
@@ -194,4 +194,4 @@ ENTRY(memmove)
tst count, #0x3f
b.ne .Ltail63
ret
-ENDPROC(memmove)
+ENDPIPROC(memmove)
diff --git a/arch/arm64/lib/memset.S b/arch/arm64/lib/memset.S
index 7c72dfd36b63..29f405f08792 100644
--- a/arch/arm64/lib/memset.S
+++ b/arch/arm64/lib/memset.S
@@ -213,4 +213,4 @@ ENTRY(memset)
ands count, count, zva_bits_x
b.ne .Ltail_maybe_long
ret
-ENDPROC(memset)
+ENDPIPROC(memset)
diff --git a/arch/arm64/lib/strcmp.S b/arch/arm64/lib/strcmp.S
index 42f828b06c59..471fe61760ef 100644
--- a/arch/arm64/lib/strcmp.S
+++ b/arch/arm64/lib/strcmp.S
@@ -231,4 +231,4 @@ CPU_BE( orr syndrome, diff, has_nul )
lsr data1, data1, #56
sub result, data1, data2, lsr #56
ret
-ENDPROC(strcmp)
+ENDPIPROC(strcmp)
diff --git a/arch/arm64/lib/strlen.S b/arch/arm64/lib/strlen.S
index 987b68b9ce44..55ccc8e24c08 100644
--- a/arch/arm64/lib/strlen.S
+++ b/arch/arm64/lib/strlen.S
@@ -123,4 +123,4 @@ CPU_LE( lsr tmp2, tmp2, tmp1 ) /* Shift (tmp1 & 63). */
csinv data1, data1, xzr, le
csel data2, data2, data2a, le
b .Lrealigned
-ENDPROC(strlen)
+ENDPIPROC(strlen)
diff --git a/arch/arm64/lib/strncmp.S b/arch/arm64/lib/strncmp.S
index 0224cf5a5533..e267044761c6 100644
--- a/arch/arm64/lib/strncmp.S
+++ b/arch/arm64/lib/strncmp.S
@@ -307,4 +307,4 @@ CPU_BE( orr syndrome, diff, has_nul )
.Lret0:
mov result, #0
ret
-ENDPROC(strncmp)
+ENDPIPROC(strncmp)
diff --git a/arch/arm64/mm/cache.S b/arch/arm64/mm/cache.S
index eb48d5df4a0f..cfa44a6adc0a 100644
--- a/arch/arm64/mm/cache.S
+++ b/arch/arm64/mm/cache.S
@@ -98,7 +98,7 @@ ENTRY(__flush_dcache_area)
b.lo 1b
dsb sy
ret
-ENDPROC(__flush_dcache_area)
+ENDPIPROC(__flush_dcache_area)
/*
* __inval_cache_range(start, end)
@@ -131,7 +131,7 @@ __dma_inv_range:
b.lo 2b
dsb sy
ret
-ENDPROC(__inval_cache_range)
+ENDPIPROC(__inval_cache_range)
ENDPROC(__dma_inv_range)
/*
@@ -171,7 +171,7 @@ ENTRY(__dma_flush_range)
b.lo 1b
dsb sy
ret
-ENDPROC(__dma_flush_range)
+ENDPIPROC(__dma_flush_range)
/*
* __dma_map_area(start, size, dir)
@@ -184,7 +184,7 @@ ENTRY(__dma_map_area)
cmp w2, #DMA_FROM_DEVICE
b.eq __dma_inv_range
b __dma_clean_range
-ENDPROC(__dma_map_area)
+ENDPIPROC(__dma_map_area)
/*
* __dma_unmap_area(start, size, dir)
@@ -197,4 +197,4 @@ ENTRY(__dma_unmap_area)
cmp w2, #DMA_TO_DEVICE
b.ne __dma_inv_range
ret
-ENDPROC(__dma_unmap_area)
+ENDPIPROC(__dma_unmap_area)
--
1.9.1
^ permalink raw reply related [flat|nested] 46+ messages in thread
* [PATCH v4 2/3] arm64: use ENDPIPROC() to annotate position independent assembler routines
@ 2015-10-08 19:02 ` Ard Biesheuvel
0 siblings, 0 replies; 46+ messages in thread
From: Ard Biesheuvel @ 2015-10-08 19:02 UTC (permalink / raw)
To: linux-arm-kernel
For more control over which functions are called with the MMU off or
with the UEFI 1:1 mapping active, annotate some assembler routines as
position independent. This is done by introducing ENDPIPROC(), which
replaces the ENDPROC() declaration of those routines.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
arch/arm64/include/asm/assembler.h | 11 +++++++++++
arch/arm64/lib/memchr.S | 2 +-
arch/arm64/lib/memcmp.S | 2 +-
arch/arm64/lib/memcpy.S | 2 +-
arch/arm64/lib/memmove.S | 2 +-
arch/arm64/lib/memset.S | 2 +-
arch/arm64/lib/strcmp.S | 2 +-
arch/arm64/lib/strlen.S | 2 +-
arch/arm64/lib/strncmp.S | 2 +-
arch/arm64/mm/cache.S | 10 +++++-----
10 files changed, 24 insertions(+), 13 deletions(-)
diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h
index b51f2cc22ca9..12eff928ef8b 100644
--- a/arch/arm64/include/asm/assembler.h
+++ b/arch/arm64/include/asm/assembler.h
@@ -193,4 +193,15 @@ lr .req x30 // link register
str \src, [\tmp, :lo12:\sym]
.endm
+/*
+ * Annotate a function as position independent, i.e., safe to be called before
+ * the kernel virtual mapping is activated.
+ */
+#define ENDPIPROC(x) \
+ .globl __pi_##x; \
+ .type __pi_##x, %function; \
+ .set __pi_##x, x; \
+ .size __pi_##x, . - x; \
+ ENDPROC(x)
+
#endif /* __ASM_ASSEMBLER_H */
diff --git a/arch/arm64/lib/memchr.S b/arch/arm64/lib/memchr.S
index 8636b7549163..4444c1d25f4b 100644
--- a/arch/arm64/lib/memchr.S
+++ b/arch/arm64/lib/memchr.S
@@ -41,4 +41,4 @@ ENTRY(memchr)
ret
2: mov x0, #0
ret
-ENDPROC(memchr)
+ENDPIPROC(memchr)
diff --git a/arch/arm64/lib/memcmp.S b/arch/arm64/lib/memcmp.S
index 6ea0776ba6de..ffbdec00327d 100644
--- a/arch/arm64/lib/memcmp.S
+++ b/arch/arm64/lib/memcmp.S
@@ -255,4 +255,4 @@ CPU_LE( rev data2, data2 )
.Lret0:
mov result, #0
ret
-ENDPROC(memcmp)
+ENDPIPROC(memcmp)
diff --git a/arch/arm64/lib/memcpy.S b/arch/arm64/lib/memcpy.S
index 173a1aace9bb..36a6a62cf263 100644
--- a/arch/arm64/lib/memcpy.S
+++ b/arch/arm64/lib/memcpy.S
@@ -71,4 +71,4 @@
ENTRY(memcpy)
#include "copy_template.S"
ret
-ENDPROC(memcpy)
+ENDPIPROC(memcpy)
diff --git a/arch/arm64/lib/memmove.S b/arch/arm64/lib/memmove.S
index 57b19ea2dad4..68e2f2035e23 100644
--- a/arch/arm64/lib/memmove.S
+++ b/arch/arm64/lib/memmove.S
@@ -194,4 +194,4 @@ ENTRY(memmove)
tst count, #0x3f
b.ne .Ltail63
ret
-ENDPROC(memmove)
+ENDPIPROC(memmove)
diff --git a/arch/arm64/lib/memset.S b/arch/arm64/lib/memset.S
index 7c72dfd36b63..29f405f08792 100644
--- a/arch/arm64/lib/memset.S
+++ b/arch/arm64/lib/memset.S
@@ -213,4 +213,4 @@ ENTRY(memset)
ands count, count, zva_bits_x
b.ne .Ltail_maybe_long
ret
-ENDPROC(memset)
+ENDPIPROC(memset)
diff --git a/arch/arm64/lib/strcmp.S b/arch/arm64/lib/strcmp.S
index 42f828b06c59..471fe61760ef 100644
--- a/arch/arm64/lib/strcmp.S
+++ b/arch/arm64/lib/strcmp.S
@@ -231,4 +231,4 @@ CPU_BE( orr syndrome, diff, has_nul )
lsr data1, data1, #56
sub result, data1, data2, lsr #56
ret
-ENDPROC(strcmp)
+ENDPIPROC(strcmp)
diff --git a/arch/arm64/lib/strlen.S b/arch/arm64/lib/strlen.S
index 987b68b9ce44..55ccc8e24c08 100644
--- a/arch/arm64/lib/strlen.S
+++ b/arch/arm64/lib/strlen.S
@@ -123,4 +123,4 @@ CPU_LE( lsr tmp2, tmp2, tmp1 ) /* Shift (tmp1 & 63). */
csinv data1, data1, xzr, le
csel data2, data2, data2a, le
b .Lrealigned
-ENDPROC(strlen)
+ENDPIPROC(strlen)
diff --git a/arch/arm64/lib/strncmp.S b/arch/arm64/lib/strncmp.S
index 0224cf5a5533..e267044761c6 100644
--- a/arch/arm64/lib/strncmp.S
+++ b/arch/arm64/lib/strncmp.S
@@ -307,4 +307,4 @@ CPU_BE( orr syndrome, diff, has_nul )
.Lret0:
mov result, #0
ret
-ENDPROC(strncmp)
+ENDPIPROC(strncmp)
diff --git a/arch/arm64/mm/cache.S b/arch/arm64/mm/cache.S
index eb48d5df4a0f..cfa44a6adc0a 100644
--- a/arch/arm64/mm/cache.S
+++ b/arch/arm64/mm/cache.S
@@ -98,7 +98,7 @@ ENTRY(__flush_dcache_area)
b.lo 1b
dsb sy
ret
-ENDPROC(__flush_dcache_area)
+ENDPIPROC(__flush_dcache_area)
/*
* __inval_cache_range(start, end)
@@ -131,7 +131,7 @@ __dma_inv_range:
b.lo 2b
dsb sy
ret
-ENDPROC(__inval_cache_range)
+ENDPIPROC(__inval_cache_range)
ENDPROC(__dma_inv_range)
/*
@@ -171,7 +171,7 @@ ENTRY(__dma_flush_range)
b.lo 1b
dsb sy
ret
-ENDPROC(__dma_flush_range)
+ENDPIPROC(__dma_flush_range)
/*
* __dma_map_area(start, size, dir)
@@ -184,7 +184,7 @@ ENTRY(__dma_map_area)
cmp w2, #DMA_FROM_DEVICE
b.eq __dma_inv_range
b __dma_clean_range
-ENDPROC(__dma_map_area)
+ENDPIPROC(__dma_map_area)
/*
* __dma_unmap_area(start, size, dir)
@@ -197,4 +197,4 @@ ENTRY(__dma_unmap_area)
cmp w2, #DMA_TO_DEVICE
b.ne __dma_inv_range
ret
-ENDPROC(__dma_unmap_area)
+ENDPIPROC(__dma_unmap_area)
--
1.9.1
^ permalink raw reply related [flat|nested] 46+ messages in thread
* [PATCH v4 3/3] arm64/efi: isolate EFI stub from the kernel proper
2015-10-08 19:02 ` Ard Biesheuvel
@ 2015-10-08 19:02 ` Ard Biesheuvel
-1 siblings, 0 replies; 46+ messages in thread
From: Ard Biesheuvel @ 2015-10-08 19:02 UTC (permalink / raw)
To: linux-efi-u79uwXL29TY76Z2rM5mHXA,
linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r,
matt.fleming-ral2JQCrhuEAvxtiuMwx3w, mark.rutland-5wv7dgnIgG8,
catalin.marinas-5wv7dgnIgG8, will.deacon-5wv7dgnIgG8,
leif.lindholm-QSEj5FYQhm4dnm+yROfE0A
Cc: ryabinin.a.a-Re5JQEeQqe8AvxtiuMwx3w, Ard Biesheuvel
Since arm64 does not use a builtin decompressor, the EFI stub is built
into the kernel proper. So far, this has been working fine, but actually,
since the stub is in fact a PE/COFF relocatable binary that is executed
at an unknown offset in the 1:1 mapping provided by the UEFI firmware, we
should not be seamlessly sharing code with the kernel proper, which is a
position dependent executable linked at a high virtual offset.
So instead, separate the contents of libstub and its dependencies, by
putting them into their own namespace by prefixing all of its symbols
with __efistub. This way, we have tight control over what parts of the
kernel proper are referenced by the stub.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
---
arch/arm64/kernel/Makefile | 12 ++++-
arch/arm64/kernel/efi-entry.S | 10 ++--
arch/arm64/kernel/head.S | 14 ++---
arch/arm64/kernel/image.h | 27 ++++++++++
drivers/firmware/efi/libstub/Makefile | 39 +++++++++++---
drivers/firmware/efi/libstub/string.c | 57 ++++++++++++++++++++
6 files changed, 139 insertions(+), 20 deletions(-)
diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
index 22dc9bc781be..7b17f6245f1e 100644
--- a/arch/arm64/kernel/Makefile
+++ b/arch/arm64/kernel/Makefile
@@ -20,6 +20,14 @@ arm64-obj-y := debug-monitors.o entry.o irq.o fpsimd.o \
cpufeature.o alternative.o cacheinfo.o \
smp.o smp_spin_table.o topology.o
+stub-obj := efi-stub.o efi-entry.o
+extra-y := $(stub-obj)
+stub-obj := $(patsubst %.o,%.stub.o,$(stub-obj))
+
+OBJCOPYFLAGS := --prefix-symbols=__efistub_
+$(obj)/%.stub.o: $(obj)/%.o FORCE
+ $(call if_changed,objcopy)
+
arm64-obj-$(CONFIG_COMPAT) += sys32.o kuser32.o signal32.o \
sys_compat.o entry32.o \
../../arm/kernel/opcodes.o
@@ -32,7 +40,7 @@ arm64-obj-$(CONFIG_CPU_PM) += sleep.o suspend.o
arm64-obj-$(CONFIG_CPU_IDLE) += cpuidle.o
arm64-obj-$(CONFIG_JUMP_LABEL) += jump_label.o
arm64-obj-$(CONFIG_KGDB) += kgdb.o
-arm64-obj-$(CONFIG_EFI) += efi.o efi-stub.o efi-entry.o
+arm64-obj-$(CONFIG_EFI) += efi.o $(stub-obj)
arm64-obj-$(CONFIG_PCI) += pci.o
arm64-obj-$(CONFIG_ARMV8_DEPRECATED) += armv8_deprecated.o
arm64-obj-$(CONFIG_ACPI) += acpi.o
@@ -40,7 +48,7 @@ arm64-obj-$(CONFIG_ACPI) += acpi.o
obj-y += $(arm64-obj-y) vdso/
obj-m += $(arm64-obj-m)
head-y := head.o
-extra-y := $(head-y) vmlinux.lds
+extra-y += $(head-y) vmlinux.lds
# vDSO - this must be built first to generate the symbol offsets
$(call objectify,$(arm64-obj-y)): $(obj)/vdso/vdso-offsets.h
diff --git a/arch/arm64/kernel/efi-entry.S b/arch/arm64/kernel/efi-entry.S
index 8ce9b0577442..a773db92908b 100644
--- a/arch/arm64/kernel/efi-entry.S
+++ b/arch/arm64/kernel/efi-entry.S
@@ -29,7 +29,7 @@
* we want to be. The kernel image wants to be placed at TEXT_OFFSET
* from start of RAM.
*/
-ENTRY(efi_stub_entry)
+ENTRY(entry)
/*
* Create a stack frame to save FP/LR with extra space
* for image_addr variable passed to efi_entry().
@@ -86,8 +86,8 @@ ENTRY(efi_stub_entry)
* entries for the VA range of the current image, so no maintenance is
* necessary.
*/
- adr x0, efi_stub_entry
- adr x1, efi_stub_entry_end
+ adr x0, entry
+ adr x1, entry_end
sub x1, x1, x0
bl __flush_dcache_area
@@ -120,5 +120,5 @@ efi_load_fail:
ldp x29, x30, [sp], #32
ret
-efi_stub_entry_end:
-ENDPROC(efi_stub_entry)
+entry_end:
+ENDPROC(entry)
diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
index 90d09eddd5b2..28a81e948df9 100644
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S
@@ -120,8 +120,8 @@ efi_head:
#endif
#ifdef CONFIG_EFI
- .globl stext_offset
- .set stext_offset, stext - efi_head
+ .globl __efistub_stext_offset
+ .set __efistub_stext_offset, stext - efi_head
.align 3
pe_header:
.ascii "PE"
@@ -144,8 +144,8 @@ optional_header:
.long _end - stext // SizeOfCode
.long 0 // SizeOfInitializedData
.long 0 // SizeOfUninitializedData
- .long efi_stub_entry - efi_head // AddressOfEntryPoint
- .long stext_offset // BaseOfCode
+ .long __efistub_entry - efi_head // AddressOfEntryPoint
+ .long __efistub_stext_offset // BaseOfCode
extra_header_fields:
.quad 0 // ImageBase
@@ -162,7 +162,7 @@ extra_header_fields:
.long _end - efi_head // SizeOfImage
// Everything before the kernel image is considered part of the header
- .long stext_offset // SizeOfHeaders
+ .long __efistub_stext_offset // SizeOfHeaders
.long 0 // CheckSum
.short 0xa // Subsystem (EFI application)
.short 0 // DllCharacteristics
@@ -207,9 +207,9 @@ section_table:
.byte 0
.byte 0 // end of 0 padding of section name
.long _end - stext // VirtualSize
- .long stext_offset // VirtualAddress
+ .long __efistub_stext_offset // VirtualAddress
.long _edata - stext // SizeOfRawData
- .long stext_offset // PointerToRawData
+ .long __efistub_stext_offset // PointerToRawData
.long 0 // PointerToRelocations (0 for executables)
.long 0 // PointerToLineNumbers (0 for executables)
diff --git a/arch/arm64/kernel/image.h b/arch/arm64/kernel/image.h
index 8fae0756e175..e083af0dd546 100644
--- a/arch/arm64/kernel/image.h
+++ b/arch/arm64/kernel/image.h
@@ -59,4 +59,31 @@
_kernel_offset_le = DATA_LE64(TEXT_OFFSET); \
_kernel_flags_le = DATA_LE64(__HEAD_FLAGS);
+#ifdef CONFIG_EFI
+
+/*
+ * The EFI stub has its own symbol namespace prefixed by __efistub_, to
+ * isolate it from the kernel proper. The following symbols are legally
+ * accessed by the stub, so provide some aliases to make them accessible.
+ * Only include data symbols here, or text symbols of functions that are
+ * guaranteed to be safe when executed at another offset than they were
+ * linked at. The routines below are all implemented in assembler in a
+ * position independent manner
+ */
+__efistub_memcmp = __pi_memcmp;
+__efistub_memchr = __pi_memchr;
+__efistub_memcpy = __pi_memcpy;
+__efistub_memmove = __pi_memmove;
+__efistub_memset = __pi_memset;
+__efistub_strlen = __pi_strlen;
+__efistub_strcmp = __pi_strcmp;
+__efistub_strncmp = __pi_strncmp;
+__efistub___flush_dcache_area = __pi___flush_dcache_area;
+
+__efistub__text = _text;
+__efistub__end = _end;
+__efistub__edata = _edata;
+
+#endif
+
#endif /* __ASM_IMAGE_H */
diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile
index 816dbe9f4b82..bca9a76cbd33 100644
--- a/drivers/firmware/efi/libstub/Makefile
+++ b/drivers/firmware/efi/libstub/Makefile
@@ -14,6 +14,8 @@ cflags-$(CONFIG_ARM64) := $(subst -pg,,$(KBUILD_CFLAGS))
cflags-$(CONFIG_ARM) := $(subst -pg,,$(KBUILD_CFLAGS)) \
-fno-builtin -fpic -mno-single-pic-base
+cflags-$(CONFIG_EFI_ARMSTUB) += -I$(srctree)/scripts/dtc/libfdt
+
KBUILD_CFLAGS := $(cflags-y) \
$(call cc-option,-ffreestanding) \
$(call cc-option,-fno-stack-protector)
@@ -22,7 +24,15 @@ GCOV_PROFILE := n
KASAN_SANITIZE := n
lib-y := efi-stub-helper.o
-lib-$(CONFIG_EFI_ARMSTUB) += arm-stub.o fdt.o
+
+# include the stub's generic dependencies from lib/ when building for ARM/arm64
+arm-deps := fdt_rw.c fdt_ro.c fdt_wip.c fdt.c fdt_empty_tree.c fdt_sw.c sort.c
+
+$(obj)/lib-%.o: $(srctree)/lib/%.c FORCE
+ $(call if_changed_rule,cc_o_c)
+
+lib-$(CONFIG_EFI_ARMSTUB) += arm-stub.o fdt.o string.o \
+ $(patsubst %.c,lib-%.o,$(arm-deps))
#
# arm64 puts the stub in the kernel proper, which will unnecessarily retain all
@@ -30,10 +40,27 @@ lib-$(CONFIG_EFI_ARMSTUB) += arm-stub.o fdt.o
# So let's apply the __init annotations at the section level, by prefixing
# the section names directly. This will ensure that even all the inline string
# literals are covered.
+# The fact that the stub and the kernel proper are essentially the same binary
+# also means that we need to be extra careful to make sure that the stub does
+# not rely on any absolute symbol references, considering that the virtual
+# kernel mapping that the linker uses is not active yet when the stub is
+# executing. So build all C dependencies of the EFI stub into libstub, and do
+# a verification pass to see if any absolute relocations exist in any of the
+# object files.
#
-extra-$(CONFIG_ARM64) := $(lib-y)
-lib-$(CONFIG_ARM64) := $(patsubst %.o,%.init.o,$(lib-y))
+extra-$(CONFIG_EFI_ARMSTUB) := $(lib-y)
+lib-$(CONFIG_EFI_ARMSTUB) := $(patsubst %.o,%.stub.o,$(lib-y))
+
+STUBCOPY_FLAGS-y := -R .debug* -R *ksymtab*
+STUBCOPY_FLAGS-$(CONFIG_ARM64) += --prefix-alloc-sections=.init \
+ --prefix-symbols=__efistub_
+STUBCOPY_RELOC-$(CONFIG_ARM64) := R_AARCH64_ABS
+
+$(obj)/%.stub.o: $(obj)/%.o FORCE
+ $(call if_changed,stubcopy)
-OBJCOPYFLAGS := --prefix-alloc-sections=.init
-$(obj)/%.init.o: $(obj)/%.o FORCE
- $(call if_changed,objcopy)
+quiet_cmd_stubcopy = STUBCPY $@
+ cmd_stubcopy = if $(OBJCOPY) $(STUBCOPY_FLAGS-y) $< $@; then \
+ $(OBJDUMP) -r $@ | grep $(STUBCOPY_RELOC-y) \
+ && (echo >&2 "$@: absolute symbol references not allowed in the EFI stub"; \
+ rm -f $@; /bin/false); else /bin/false; fi
diff --git a/drivers/firmware/efi/libstub/string.c b/drivers/firmware/efi/libstub/string.c
new file mode 100644
index 000000000000..09d5a0894343
--- /dev/null
+++ b/drivers/firmware/efi/libstub/string.c
@@ -0,0 +1,57 @@
+/*
+ * Taken from:
+ * linux/lib/string.c
+ *
+ * Copyright (C) 1991, 1992 Linus Torvalds
+ */
+
+#include <linux/types.h>
+#include <linux/string.h>
+
+#ifndef __HAVE_ARCH_STRSTR
+/**
+ * strstr - Find the first substring in a %NUL terminated string
+ * @s1: The string to be searched
+ * @s2: The string to search for
+ */
+char *strstr(const char *s1, const char *s2)
+{
+ size_t l1, l2;
+
+ l2 = strlen(s2);
+ if (!l2)
+ return (char *)s1;
+ l1 = strlen(s1);
+ while (l1 >= l2) {
+ l1--;
+ if (!memcmp(s1, s2, l2))
+ return (char *)s1;
+ s1++;
+ }
+ return NULL;
+}
+#endif
+
+#ifndef __HAVE_ARCH_STRNCMP
+/**
+ * strncmp - Compare two length-limited strings
+ * @cs: One string
+ * @ct: Another string
+ * @count: The maximum number of bytes to compare
+ */
+int strncmp(const char *cs, const char *ct, size_t count)
+{
+ unsigned char c1, c2;
+
+ while (count) {
+ c1 = *cs++;
+ c2 = *ct++;
+ if (c1 != c2)
+ return c1 < c2 ? -1 : 1;
+ if (!c1)
+ break;
+ count--;
+ }
+ return 0;
+}
+#endif
--
1.9.1
^ permalink raw reply related [flat|nested] 46+ messages in thread
* [PATCH v4 3/3] arm64/efi: isolate EFI stub from the kernel proper
@ 2015-10-08 19:02 ` Ard Biesheuvel
0 siblings, 0 replies; 46+ messages in thread
From: Ard Biesheuvel @ 2015-10-08 19:02 UTC (permalink / raw)
To: linux-arm-kernel
Since arm64 does not use a builtin decompressor, the EFI stub is built
into the kernel proper. So far, this has been working fine, but actually,
since the stub is in fact a PE/COFF relocatable binary that is executed
at an unknown offset in the 1:1 mapping provided by the UEFI firmware, we
should not be seamlessly sharing code with the kernel proper, which is a
position dependent executable linked at a high virtual offset.
So instead, separate the contents of libstub and its dependencies, by
putting them into their own namespace by prefixing all of its symbols
with __efistub. This way, we have tight control over what parts of the
kernel proper are referenced by the stub.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
arch/arm64/kernel/Makefile | 12 ++++-
arch/arm64/kernel/efi-entry.S | 10 ++--
arch/arm64/kernel/head.S | 14 ++---
arch/arm64/kernel/image.h | 27 ++++++++++
drivers/firmware/efi/libstub/Makefile | 39 +++++++++++---
drivers/firmware/efi/libstub/string.c | 57 ++++++++++++++++++++
6 files changed, 139 insertions(+), 20 deletions(-)
diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
index 22dc9bc781be..7b17f6245f1e 100644
--- a/arch/arm64/kernel/Makefile
+++ b/arch/arm64/kernel/Makefile
@@ -20,6 +20,14 @@ arm64-obj-y := debug-monitors.o entry.o irq.o fpsimd.o \
cpufeature.o alternative.o cacheinfo.o \
smp.o smp_spin_table.o topology.o
+stub-obj := efi-stub.o efi-entry.o
+extra-y := $(stub-obj)
+stub-obj := $(patsubst %.o,%.stub.o,$(stub-obj))
+
+OBJCOPYFLAGS := --prefix-symbols=__efistub_
+$(obj)/%.stub.o: $(obj)/%.o FORCE
+ $(call if_changed,objcopy)
+
arm64-obj-$(CONFIG_COMPAT) += sys32.o kuser32.o signal32.o \
sys_compat.o entry32.o \
../../arm/kernel/opcodes.o
@@ -32,7 +40,7 @@ arm64-obj-$(CONFIG_CPU_PM) += sleep.o suspend.o
arm64-obj-$(CONFIG_CPU_IDLE) += cpuidle.o
arm64-obj-$(CONFIG_JUMP_LABEL) += jump_label.o
arm64-obj-$(CONFIG_KGDB) += kgdb.o
-arm64-obj-$(CONFIG_EFI) += efi.o efi-stub.o efi-entry.o
+arm64-obj-$(CONFIG_EFI) += efi.o $(stub-obj)
arm64-obj-$(CONFIG_PCI) += pci.o
arm64-obj-$(CONFIG_ARMV8_DEPRECATED) += armv8_deprecated.o
arm64-obj-$(CONFIG_ACPI) += acpi.o
@@ -40,7 +48,7 @@ arm64-obj-$(CONFIG_ACPI) += acpi.o
obj-y += $(arm64-obj-y) vdso/
obj-m += $(arm64-obj-m)
head-y := head.o
-extra-y := $(head-y) vmlinux.lds
+extra-y += $(head-y) vmlinux.lds
# vDSO - this must be built first to generate the symbol offsets
$(call objectify,$(arm64-obj-y)): $(obj)/vdso/vdso-offsets.h
diff --git a/arch/arm64/kernel/efi-entry.S b/arch/arm64/kernel/efi-entry.S
index 8ce9b0577442..a773db92908b 100644
--- a/arch/arm64/kernel/efi-entry.S
+++ b/arch/arm64/kernel/efi-entry.S
@@ -29,7 +29,7 @@
* we want to be. The kernel image wants to be placed at TEXT_OFFSET
* from start of RAM.
*/
-ENTRY(efi_stub_entry)
+ENTRY(entry)
/*
* Create a stack frame to save FP/LR with extra space
* for image_addr variable passed to efi_entry().
@@ -86,8 +86,8 @@ ENTRY(efi_stub_entry)
* entries for the VA range of the current image, so no maintenance is
* necessary.
*/
- adr x0, efi_stub_entry
- adr x1, efi_stub_entry_end
+ adr x0, entry
+ adr x1, entry_end
sub x1, x1, x0
bl __flush_dcache_area
@@ -120,5 +120,5 @@ efi_load_fail:
ldp x29, x30, [sp], #32
ret
-efi_stub_entry_end:
-ENDPROC(efi_stub_entry)
+entry_end:
+ENDPROC(entry)
diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
index 90d09eddd5b2..28a81e948df9 100644
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S
@@ -120,8 +120,8 @@ efi_head:
#endif
#ifdef CONFIG_EFI
- .globl stext_offset
- .set stext_offset, stext - efi_head
+ .globl __efistub_stext_offset
+ .set __efistub_stext_offset, stext - efi_head
.align 3
pe_header:
.ascii "PE"
@@ -144,8 +144,8 @@ optional_header:
.long _end - stext // SizeOfCode
.long 0 // SizeOfInitializedData
.long 0 // SizeOfUninitializedData
- .long efi_stub_entry - efi_head // AddressOfEntryPoint
- .long stext_offset // BaseOfCode
+ .long __efistub_entry - efi_head // AddressOfEntryPoint
+ .long __efistub_stext_offset // BaseOfCode
extra_header_fields:
.quad 0 // ImageBase
@@ -162,7 +162,7 @@ extra_header_fields:
.long _end - efi_head // SizeOfImage
// Everything before the kernel image is considered part of the header
- .long stext_offset // SizeOfHeaders
+ .long __efistub_stext_offset // SizeOfHeaders
.long 0 // CheckSum
.short 0xa // Subsystem (EFI application)
.short 0 // DllCharacteristics
@@ -207,9 +207,9 @@ section_table:
.byte 0
.byte 0 // end of 0 padding of section name
.long _end - stext // VirtualSize
- .long stext_offset // VirtualAddress
+ .long __efistub_stext_offset // VirtualAddress
.long _edata - stext // SizeOfRawData
- .long stext_offset // PointerToRawData
+ .long __efistub_stext_offset // PointerToRawData
.long 0 // PointerToRelocations (0 for executables)
.long 0 // PointerToLineNumbers (0 for executables)
diff --git a/arch/arm64/kernel/image.h b/arch/arm64/kernel/image.h
index 8fae0756e175..e083af0dd546 100644
--- a/arch/arm64/kernel/image.h
+++ b/arch/arm64/kernel/image.h
@@ -59,4 +59,31 @@
_kernel_offset_le = DATA_LE64(TEXT_OFFSET); \
_kernel_flags_le = DATA_LE64(__HEAD_FLAGS);
+#ifdef CONFIG_EFI
+
+/*
+ * The EFI stub has its own symbol namespace prefixed by __efistub_, to
+ * isolate it from the kernel proper. The following symbols are legally
+ * accessed by the stub, so provide some aliases to make them accessible.
+ * Only include data symbols here, or text symbols of functions that are
+ * guaranteed to be safe when executed at another offset than they were
+ * linked at. The routines below are all implemented in assembler in a
+ * position independent manner
+ */
+__efistub_memcmp = __pi_memcmp;
+__efistub_memchr = __pi_memchr;
+__efistub_memcpy = __pi_memcpy;
+__efistub_memmove = __pi_memmove;
+__efistub_memset = __pi_memset;
+__efistub_strlen = __pi_strlen;
+__efistub_strcmp = __pi_strcmp;
+__efistub_strncmp = __pi_strncmp;
+__efistub___flush_dcache_area = __pi___flush_dcache_area;
+
+__efistub__text = _text;
+__efistub__end = _end;
+__efistub__edata = _edata;
+
+#endif
+
#endif /* __ASM_IMAGE_H */
diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile
index 816dbe9f4b82..bca9a76cbd33 100644
--- a/drivers/firmware/efi/libstub/Makefile
+++ b/drivers/firmware/efi/libstub/Makefile
@@ -14,6 +14,8 @@ cflags-$(CONFIG_ARM64) := $(subst -pg,,$(KBUILD_CFLAGS))
cflags-$(CONFIG_ARM) := $(subst -pg,,$(KBUILD_CFLAGS)) \
-fno-builtin -fpic -mno-single-pic-base
+cflags-$(CONFIG_EFI_ARMSTUB) += -I$(srctree)/scripts/dtc/libfdt
+
KBUILD_CFLAGS := $(cflags-y) \
$(call cc-option,-ffreestanding) \
$(call cc-option,-fno-stack-protector)
@@ -22,7 +24,15 @@ GCOV_PROFILE := n
KASAN_SANITIZE := n
lib-y := efi-stub-helper.o
-lib-$(CONFIG_EFI_ARMSTUB) += arm-stub.o fdt.o
+
+# include the stub's generic dependencies from lib/ when building for ARM/arm64
+arm-deps := fdt_rw.c fdt_ro.c fdt_wip.c fdt.c fdt_empty_tree.c fdt_sw.c sort.c
+
+$(obj)/lib-%.o: $(srctree)/lib/%.c FORCE
+ $(call if_changed_rule,cc_o_c)
+
+lib-$(CONFIG_EFI_ARMSTUB) += arm-stub.o fdt.o string.o \
+ $(patsubst %.c,lib-%.o,$(arm-deps))
#
# arm64 puts the stub in the kernel proper, which will unnecessarily retain all
@@ -30,10 +40,27 @@ lib-$(CONFIG_EFI_ARMSTUB) += arm-stub.o fdt.o
# So let's apply the __init annotations at the section level, by prefixing
# the section names directly. This will ensure that even all the inline string
# literals are covered.
+# The fact that the stub and the kernel proper are essentially the same binary
+# also means that we need to be extra careful to make sure that the stub does
+# not rely on any absolute symbol references, considering that the virtual
+# kernel mapping that the linker uses is not active yet when the stub is
+# executing. So build all C dependencies of the EFI stub into libstub, and do
+# a verification pass to see if any absolute relocations exist in any of the
+# object files.
#
-extra-$(CONFIG_ARM64) := $(lib-y)
-lib-$(CONFIG_ARM64) := $(patsubst %.o,%.init.o,$(lib-y))
+extra-$(CONFIG_EFI_ARMSTUB) := $(lib-y)
+lib-$(CONFIG_EFI_ARMSTUB) := $(patsubst %.o,%.stub.o,$(lib-y))
+
+STUBCOPY_FLAGS-y := -R .debug* -R *ksymtab*
+STUBCOPY_FLAGS-$(CONFIG_ARM64) += --prefix-alloc-sections=.init \
+ --prefix-symbols=__efistub_
+STUBCOPY_RELOC-$(CONFIG_ARM64) := R_AARCH64_ABS
+
+$(obj)/%.stub.o: $(obj)/%.o FORCE
+ $(call if_changed,stubcopy)
-OBJCOPYFLAGS := --prefix-alloc-sections=.init
-$(obj)/%.init.o: $(obj)/%.o FORCE
- $(call if_changed,objcopy)
+quiet_cmd_stubcopy = STUBCPY $@
+ cmd_stubcopy = if $(OBJCOPY) $(STUBCOPY_FLAGS-y) $< $@; then \
+ $(OBJDUMP) -r $@ | grep $(STUBCOPY_RELOC-y) \
+ && (echo >&2 "$@: absolute symbol references not allowed in the EFI stub"; \
+ rm -f $@; /bin/false); else /bin/false; fi
diff --git a/drivers/firmware/efi/libstub/string.c b/drivers/firmware/efi/libstub/string.c
new file mode 100644
index 000000000000..09d5a0894343
--- /dev/null
+++ b/drivers/firmware/efi/libstub/string.c
@@ -0,0 +1,57 @@
+/*
+ * Taken from:
+ * linux/lib/string.c
+ *
+ * Copyright (C) 1991, 1992 Linus Torvalds
+ */
+
+#include <linux/types.h>
+#include <linux/string.h>
+
+#ifndef __HAVE_ARCH_STRSTR
+/**
+ * strstr - Find the first substring in a %NUL terminated string
+ * @s1: The string to be searched
+ * @s2: The string to search for
+ */
+char *strstr(const char *s1, const char *s2)
+{
+ size_t l1, l2;
+
+ l2 = strlen(s2);
+ if (!l2)
+ return (char *)s1;
+ l1 = strlen(s1);
+ while (l1 >= l2) {
+ l1--;
+ if (!memcmp(s1, s2, l2))
+ return (char *)s1;
+ s1++;
+ }
+ return NULL;
+}
+#endif
+
+#ifndef __HAVE_ARCH_STRNCMP
+/**
+ * strncmp - Compare two length-limited strings
+ * @cs: One string
+ * @ct: Another string
+ * @count: The maximum number of bytes to compare
+ */
+int strncmp(const char *cs, const char *ct, size_t count)
+{
+ unsigned char c1, c2;
+
+ while (count) {
+ c1 = *cs++;
+ c2 = *ct++;
+ if (c1 != c2)
+ return c1 < c2 ? -1 : 1;
+ if (!c1)
+ break;
+ count--;
+ }
+ return 0;
+}
+#endif
--
1.9.1
^ permalink raw reply related [flat|nested] 46+ messages in thread
* Re: [PATCH v4 3/3] arm64/efi: isolate EFI stub from the kernel proper
2015-10-08 19:02 ` Ard Biesheuvel
@ 2015-10-09 8:12 ` Andrey Ryabinin
-1 siblings, 0 replies; 46+ messages in thread
From: Andrey Ryabinin @ 2015-10-09 8:12 UTC (permalink / raw)
To: Ard Biesheuvel
Cc: linux-efi-u79uwXL29TY76Z2rM5mHXA,
linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r, Matt Fleming,
Mark Rutland, Catalin Marinas, Will Deacon, Leif Lindholm
2015-10-08 22:02 GMT+03:00 Ard Biesheuvel <ard.biesheuvel-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>:
> --- a/arch/arm64/kernel/image.h
> +++ b/arch/arm64/kernel/image.h
> @@ -59,4 +59,31 @@
> _kernel_offset_le = DATA_LE64(TEXT_OFFSET); \
> _kernel_flags_le = DATA_LE64(__HEAD_FLAGS);
>
> +#ifdef CONFIG_EFI
> +
> +/*
> + * The EFI stub has its own symbol namespace prefixed by __efistub_, to
> + * isolate it from the kernel proper. The following symbols are legally
> + * accessed by the stub, so provide some aliases to make them accessible.
> + * Only include data symbols here, or text symbols of functions that are
> + * guaranteed to be safe when executed at another offset than they were
> + * linked at. The routines below are all implemented in assembler in a
> + * position independent manner
> + */
> +__efistub_memcmp = __pi_memcmp;
> +__efistub_memchr = __pi_memchr;
> +__efistub_memcpy = __pi_memcpy;
> +__efistub_memmove = __pi_memmove;
> +__efistub_memset = __pi_memset;
> +__efistub_strlen = __pi_strlen;
> +__efistub_strcmp = __pi_strcmp;
> +__efistub_strncmp = __pi_strncmp;
> +__efistub___flush_dcache_area = __pi___flush_dcache_area;
So why we need these __pi_* aliases?
We could just do __efistub_memcmp = memcmp; Right?
> +
> +__efistub__text = _text;
> +__efistub__end = _end;
> +__efistub__edata = _edata;
> +
> +#endif
^ permalink raw reply [flat|nested] 46+ messages in thread
* [PATCH v4 3/3] arm64/efi: isolate EFI stub from the kernel proper
@ 2015-10-09 8:12 ` Andrey Ryabinin
0 siblings, 0 replies; 46+ messages in thread
From: Andrey Ryabinin @ 2015-10-09 8:12 UTC (permalink / raw)
To: linux-arm-kernel
2015-10-08 22:02 GMT+03:00 Ard Biesheuvel <ard.biesheuvel@linaro.org>:
> --- a/arch/arm64/kernel/image.h
> +++ b/arch/arm64/kernel/image.h
> @@ -59,4 +59,31 @@
> _kernel_offset_le = DATA_LE64(TEXT_OFFSET); \
> _kernel_flags_le = DATA_LE64(__HEAD_FLAGS);
>
> +#ifdef CONFIG_EFI
> +
> +/*
> + * The EFI stub has its own symbol namespace prefixed by __efistub_, to
> + * isolate it from the kernel proper. The following symbols are legally
> + * accessed by the stub, so provide some aliases to make them accessible.
> + * Only include data symbols here, or text symbols of functions that are
> + * guaranteed to be safe when executed at another offset than they were
> + * linked at. The routines below are all implemented in assembler in a
> + * position independent manner
> + */
> +__efistub_memcmp = __pi_memcmp;
> +__efistub_memchr = __pi_memchr;
> +__efistub_memcpy = __pi_memcpy;
> +__efistub_memmove = __pi_memmove;
> +__efistub_memset = __pi_memset;
> +__efistub_strlen = __pi_strlen;
> +__efistub_strcmp = __pi_strcmp;
> +__efistub_strncmp = __pi_strncmp;
> +__efistub___flush_dcache_area = __pi___flush_dcache_area;
So why we need these __pi_* aliases?
We could just do __efistub_memcmp = memcmp; Right?
> +
> +__efistub__text = _text;
> +__efistub__end = _end;
> +__efistub__edata = _edata;
> +
> +#endif
^ permalink raw reply [flat|nested] 46+ messages in thread
* Re: [PATCH v4 3/3] arm64/efi: isolate EFI stub from the kernel proper
2015-10-09 8:12 ` Andrey Ryabinin
@ 2015-10-09 9:10 ` Will Deacon
-1 siblings, 0 replies; 46+ messages in thread
From: Will Deacon @ 2015-10-09 9:10 UTC (permalink / raw)
To: Andrey Ryabinin
Cc: Ard Biesheuvel, linux-efi-u79uwXL29TY76Z2rM5mHXA,
linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r, Matt Fleming,
Mark Rutland, Catalin Marinas, Leif Lindholm
On Fri, Oct 09, 2015 at 11:12:24AM +0300, Andrey Ryabinin wrote:
> 2015-10-08 22:02 GMT+03:00 Ard Biesheuvel <ard.biesheuvel-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>:
> > --- a/arch/arm64/kernel/image.h
> > +++ b/arch/arm64/kernel/image.h
> > @@ -59,4 +59,31 @@
> > _kernel_offset_le = DATA_LE64(TEXT_OFFSET); \
> > _kernel_flags_le = DATA_LE64(__HEAD_FLAGS);
> >
> > +#ifdef CONFIG_EFI
> > +
> > +/*
> > + * The EFI stub has its own symbol namespace prefixed by __efistub_, to
> > + * isolate it from the kernel proper. The following symbols are legally
> > + * accessed by the stub, so provide some aliases to make them accessible.
> > + * Only include data symbols here, or text symbols of functions that are
> > + * guaranteed to be safe when executed at another offset than they were
> > + * linked at. The routines below are all implemented in assembler in a
> > + * position independent manner
> > + */
> > +__efistub_memcmp = __pi_memcmp;
> > +__efistub_memchr = __pi_memchr;
> > +__efistub_memcpy = __pi_memcpy;
> > +__efistub_memmove = __pi_memmove;
> > +__efistub_memset = __pi_memset;
> > +__efistub_strlen = __pi_strlen;
> > +__efistub_strcmp = __pi_strcmp;
> > +__efistub_strncmp = __pi_strncmp;
> > +__efistub___flush_dcache_area = __pi___flush_dcache_area;
>
> So why we need these __pi_* aliases?
> We could just do __efistub_memcmp = memcmp; Right?
We *could*, but that defeats the whole purpose of tagging
position-independent functions explicitly in the kernel text.
Will
^ permalink raw reply [flat|nested] 46+ messages in thread
* [PATCH v4 3/3] arm64/efi: isolate EFI stub from the kernel proper
@ 2015-10-09 9:10 ` Will Deacon
0 siblings, 0 replies; 46+ messages in thread
From: Will Deacon @ 2015-10-09 9:10 UTC (permalink / raw)
To: linux-arm-kernel
On Fri, Oct 09, 2015 at 11:12:24AM +0300, Andrey Ryabinin wrote:
> 2015-10-08 22:02 GMT+03:00 Ard Biesheuvel <ard.biesheuvel@linaro.org>:
> > --- a/arch/arm64/kernel/image.h
> > +++ b/arch/arm64/kernel/image.h
> > @@ -59,4 +59,31 @@
> > _kernel_offset_le = DATA_LE64(TEXT_OFFSET); \
> > _kernel_flags_le = DATA_LE64(__HEAD_FLAGS);
> >
> > +#ifdef CONFIG_EFI
> > +
> > +/*
> > + * The EFI stub has its own symbol namespace prefixed by __efistub_, to
> > + * isolate it from the kernel proper. The following symbols are legally
> > + * accessed by the stub, so provide some aliases to make them accessible.
> > + * Only include data symbols here, or text symbols of functions that are
> > + * guaranteed to be safe when executed at another offset than they were
> > + * linked at. The routines below are all implemented in assembler in a
> > + * position independent manner
> > + */
> > +__efistub_memcmp = __pi_memcmp;
> > +__efistub_memchr = __pi_memchr;
> > +__efistub_memcpy = __pi_memcpy;
> > +__efistub_memmove = __pi_memmove;
> > +__efistub_memset = __pi_memset;
> > +__efistub_strlen = __pi_strlen;
> > +__efistub_strcmp = __pi_strcmp;
> > +__efistub_strncmp = __pi_strncmp;
> > +__efistub___flush_dcache_area = __pi___flush_dcache_area;
>
> So why we need these __pi_* aliases?
> We could just do __efistub_memcmp = memcmp; Right?
We *could*, but that defeats the whole purpose of tagging
position-independent functions explicitly in the kernel text.
Will
^ permalink raw reply [flat|nested] 46+ messages in thread
* Re: [PATCH v4 3/3] arm64/efi: isolate EFI stub from the kernel proper
2015-10-09 9:10 ` Will Deacon
@ 2015-10-09 9:40 ` Andrey Ryabinin
-1 siblings, 0 replies; 46+ messages in thread
From: Andrey Ryabinin @ 2015-10-09 9:40 UTC (permalink / raw)
To: Will Deacon
Cc: Mark Rutland, linux-efi, Ard Biesheuvel, Catalin Marinas,
Leif Lindholm, Matt Fleming, linux-arm-kernel
2015-10-09 12:10 GMT+03:00 Will Deacon <will.deacon@arm.com>:
> On Fri, Oct 09, 2015 at 11:12:24AM +0300, Andrey Ryabinin wrote:
>> 2015-10-08 22:02 GMT+03:00 Ard Biesheuvel <ard.biesheuvel@linaro.org>:
>> > --- a/arch/arm64/kernel/image.h
>> > +++ b/arch/arm64/kernel/image.h
>> > @@ -59,4 +59,31 @@
>> > _kernel_offset_le = DATA_LE64(TEXT_OFFSET); \
>> > _kernel_flags_le = DATA_LE64(__HEAD_FLAGS);
>> >
>> > +#ifdef CONFIG_EFI
>> > +
>> > +/*
>> > + * The EFI stub has its own symbol namespace prefixed by __efistub_, to
>> > + * isolate it from the kernel proper. The following symbols are legally
>> > + * accessed by the stub, so provide some aliases to make them accessible.
>> > + * Only include data symbols here, or text symbols of functions that are
>> > + * guaranteed to be safe when executed at another offset than they were
>> > + * linked at. The routines below are all implemented in assembler in a
>> > + * position independent manner
>> > + */
>> > +__efistub_memcmp = __pi_memcmp;
>> > +__efistub_memchr = __pi_memchr;
>> > +__efistub_memcpy = __pi_memcpy;
>> > +__efistub_memmove = __pi_memmove;
>> > +__efistub_memset = __pi_memset;
>> > +__efistub_strlen = __pi_strlen;
>> > +__efistub_strcmp = __pi_strcmp;
>> > +__efistub_strncmp = __pi_strncmp;
>> > +__efistub___flush_dcache_area = __pi___flush_dcache_area;
>>
>> So why we need these __pi_* aliases?
>> We could just do __efistub_memcmp = memcmp; Right?
>
> We *could*, but that defeats the whole purpose of tagging
> position-independent functions explicitly in the kernel text.
>
I just don't get that "the whole purpose of tagging".
Yes, the EFI stub is allowed to call only PI kernel functions.
But the EFI stub already protected by __efistub_ namespace.
If we want to use some new PI function in the stub, we would need add
it into this list at first.
So that __pi_ namespace doesn't bring any protection or isolation.
^ permalink raw reply [flat|nested] 46+ messages in thread
* [PATCH v4 3/3] arm64/efi: isolate EFI stub from the kernel proper
@ 2015-10-09 9:40 ` Andrey Ryabinin
0 siblings, 0 replies; 46+ messages in thread
From: Andrey Ryabinin @ 2015-10-09 9:40 UTC (permalink / raw)
To: linux-arm-kernel
2015-10-09 12:10 GMT+03:00 Will Deacon <will.deacon@arm.com>:
> On Fri, Oct 09, 2015 at 11:12:24AM +0300, Andrey Ryabinin wrote:
>> 2015-10-08 22:02 GMT+03:00 Ard Biesheuvel <ard.biesheuvel@linaro.org>:
>> > --- a/arch/arm64/kernel/image.h
>> > +++ b/arch/arm64/kernel/image.h
>> > @@ -59,4 +59,31 @@
>> > _kernel_offset_le = DATA_LE64(TEXT_OFFSET); \
>> > _kernel_flags_le = DATA_LE64(__HEAD_FLAGS);
>> >
>> > +#ifdef CONFIG_EFI
>> > +
>> > +/*
>> > + * The EFI stub has its own symbol namespace prefixed by __efistub_, to
>> > + * isolate it from the kernel proper. The following symbols are legally
>> > + * accessed by the stub, so provide some aliases to make them accessible.
>> > + * Only include data symbols here, or text symbols of functions that are
>> > + * guaranteed to be safe when executed at another offset than they were
>> > + * linked at. The routines below are all implemented in assembler in a
>> > + * position independent manner
>> > + */
>> > +__efistub_memcmp = __pi_memcmp;
>> > +__efistub_memchr = __pi_memchr;
>> > +__efistub_memcpy = __pi_memcpy;
>> > +__efistub_memmove = __pi_memmove;
>> > +__efistub_memset = __pi_memset;
>> > +__efistub_strlen = __pi_strlen;
>> > +__efistub_strcmp = __pi_strcmp;
>> > +__efistub_strncmp = __pi_strncmp;
>> > +__efistub___flush_dcache_area = __pi___flush_dcache_area;
>>
>> So why we need these __pi_* aliases?
>> We could just do __efistub_memcmp = memcmp; Right?
>
> We *could*, but that defeats the whole purpose of tagging
> position-independent functions explicitly in the kernel text.
>
I just don't get that "the whole purpose of tagging".
Yes, the EFI stub is allowed to call only PI kernel functions.
But the EFI stub already protected by __efistub_ namespace.
If we want to use some new PI function in the stub, we would need add
it into this list at first.
So that __pi_ namespace doesn't bring any protection or isolation.
^ permalink raw reply [flat|nested] 46+ messages in thread
* Re: [PATCH v4 3/3] arm64/efi: isolate EFI stub from the kernel proper
2015-10-09 9:40 ` Andrey Ryabinin
@ 2015-10-09 9:43 ` Will Deacon
-1 siblings, 0 replies; 46+ messages in thread
From: Will Deacon @ 2015-10-09 9:43 UTC (permalink / raw)
To: Andrey Ryabinin
Cc: Ard Biesheuvel, linux-efi-u79uwXL29TY76Z2rM5mHXA,
linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r, Matt Fleming,
Mark Rutland, Catalin Marinas, Leif Lindholm
On Fri, Oct 09, 2015 at 12:40:21PM +0300, Andrey Ryabinin wrote:
> 2015-10-09 12:10 GMT+03:00 Will Deacon <will.deacon-5wv7dgnIgG8@public.gmane.org>:
> > On Fri, Oct 09, 2015 at 11:12:24AM +0300, Andrey Ryabinin wrote:
> >> 2015-10-08 22:02 GMT+03:00 Ard Biesheuvel <ard.biesheuvel-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>:
> >> > --- a/arch/arm64/kernel/image.h
> >> > +++ b/arch/arm64/kernel/image.h
> >> > @@ -59,4 +59,31 @@
> >> > _kernel_offset_le = DATA_LE64(TEXT_OFFSET); \
> >> > _kernel_flags_le = DATA_LE64(__HEAD_FLAGS);
> >> >
> >> > +#ifdef CONFIG_EFI
> >> > +
> >> > +/*
> >> > + * The EFI stub has its own symbol namespace prefixed by __efistub_, to
> >> > + * isolate it from the kernel proper. The following symbols are legally
> >> > + * accessed by the stub, so provide some aliases to make them accessible.
> >> > + * Only include data symbols here, or text symbols of functions that are
> >> > + * guaranteed to be safe when executed at another offset than they were
> >> > + * linked at. The routines below are all implemented in assembler in a
> >> > + * position independent manner
> >> > + */
> >> > +__efistub_memcmp = __pi_memcmp;
> >> > +__efistub_memchr = __pi_memchr;
> >> > +__efistub_memcpy = __pi_memcpy;
> >> > +__efistub_memmove = __pi_memmove;
> >> > +__efistub_memset = __pi_memset;
> >> > +__efistub_strlen = __pi_strlen;
> >> > +__efistub_strcmp = __pi_strcmp;
> >> > +__efistub_strncmp = __pi_strncmp;
> >> > +__efistub___flush_dcache_area = __pi___flush_dcache_area;
> >>
> >> So why we need these __pi_* aliases?
> >> We could just do __efistub_memcmp = memcmp; Right?
> >
> > We *could*, but that defeats the whole purpose of tagging
> > position-independent functions explicitly in the kernel text.
> >
>
> I just don't get that "the whole purpose of tagging".
>
> Yes, the EFI stub is allowed to call only PI kernel functions.
> But the EFI stub already protected by __efistub_ namespace.
> If we want to use some new PI function in the stub, we would need add
> it into this list at first.
> So that __pi_ namespace doesn't bring any protection or isolation.
What it does it force people making future changes to the __pi_* functions
to think about the stub, otherwise if the function happens to be
position-independent when efistub starts using it, it could easily break
due to some future patch where the author didn't realise that it was
being used in that manner.
Will
^ permalink raw reply [flat|nested] 46+ messages in thread
* [PATCH v4 3/3] arm64/efi: isolate EFI stub from the kernel proper
@ 2015-10-09 9:43 ` Will Deacon
0 siblings, 0 replies; 46+ messages in thread
From: Will Deacon @ 2015-10-09 9:43 UTC (permalink / raw)
To: linux-arm-kernel
On Fri, Oct 09, 2015 at 12:40:21PM +0300, Andrey Ryabinin wrote:
> 2015-10-09 12:10 GMT+03:00 Will Deacon <will.deacon@arm.com>:
> > On Fri, Oct 09, 2015 at 11:12:24AM +0300, Andrey Ryabinin wrote:
> >> 2015-10-08 22:02 GMT+03:00 Ard Biesheuvel <ard.biesheuvel@linaro.org>:
> >> > --- a/arch/arm64/kernel/image.h
> >> > +++ b/arch/arm64/kernel/image.h
> >> > @@ -59,4 +59,31 @@
> >> > _kernel_offset_le = DATA_LE64(TEXT_OFFSET); \
> >> > _kernel_flags_le = DATA_LE64(__HEAD_FLAGS);
> >> >
> >> > +#ifdef CONFIG_EFI
> >> > +
> >> > +/*
> >> > + * The EFI stub has its own symbol namespace prefixed by __efistub_, to
> >> > + * isolate it from the kernel proper. The following symbols are legally
> >> > + * accessed by the stub, so provide some aliases to make them accessible.
> >> > + * Only include data symbols here, or text symbols of functions that are
> >> > + * guaranteed to be safe when executed at another offset than they were
> >> > + * linked at. The routines below are all implemented in assembler in a
> >> > + * position independent manner
> >> > + */
> >> > +__efistub_memcmp = __pi_memcmp;
> >> > +__efistub_memchr = __pi_memchr;
> >> > +__efistub_memcpy = __pi_memcpy;
> >> > +__efistub_memmove = __pi_memmove;
> >> > +__efistub_memset = __pi_memset;
> >> > +__efistub_strlen = __pi_strlen;
> >> > +__efistub_strcmp = __pi_strcmp;
> >> > +__efistub_strncmp = __pi_strncmp;
> >> > +__efistub___flush_dcache_area = __pi___flush_dcache_area;
> >>
> >> So why we need these __pi_* aliases?
> >> We could just do __efistub_memcmp = memcmp; Right?
> >
> > We *could*, but that defeats the whole purpose of tagging
> > position-independent functions explicitly in the kernel text.
> >
>
> I just don't get that "the whole purpose of tagging".
>
> Yes, the EFI stub is allowed to call only PI kernel functions.
> But the EFI stub already protected by __efistub_ namespace.
> If we want to use some new PI function in the stub, we would need add
> it into this list at first.
> So that __pi_ namespace doesn't bring any protection or isolation.
What it does it force people making future changes to the __pi_* functions
to think about the stub, otherwise if the function happens to be
position-independent when efistub starts using it, it could easily break
due to some future patch where the author didn't realise that it was
being used in that manner.
Will
^ permalink raw reply [flat|nested] 46+ messages in thread
* Re: [PATCH v4 3/3] arm64/efi: isolate EFI stub from the kernel proper
2015-10-09 9:43 ` Will Deacon
@ 2015-10-09 9:48 ` Andrey Ryabinin
-1 siblings, 0 replies; 46+ messages in thread
From: Andrey Ryabinin @ 2015-10-09 9:48 UTC (permalink / raw)
To: Will Deacon
Cc: Ard Biesheuvel, linux-efi-u79uwXL29TY76Z2rM5mHXA,
linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r, Matt Fleming,
Mark Rutland, Catalin Marinas, Leif Lindholm
2015-10-09 12:43 GMT+03:00 Will Deacon <will.deacon-5wv7dgnIgG8@public.gmane.org>:
> On Fri, Oct 09, 2015 at 12:40:21PM +0300, Andrey Ryabinin wrote:
>> 2015-10-09 12:10 GMT+03:00 Will Deacon <will.deacon-5wv7dgnIgG8@public.gmane.org>:
>> > On Fri, Oct 09, 2015 at 11:12:24AM +0300, Andrey Ryabinin wrote:
>> >> 2015-10-08 22:02 GMT+03:00 Ard Biesheuvel <ard.biesheuvel-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>:
>> >> > --- a/arch/arm64/kernel/image.h
>> >> > +++ b/arch/arm64/kernel/image.h
>> >> > @@ -59,4 +59,31 @@
>> >> > _kernel_offset_le = DATA_LE64(TEXT_OFFSET); \
>> >> > _kernel_flags_le = DATA_LE64(__HEAD_FLAGS);
>> >> >
>> >> > +#ifdef CONFIG_EFI
>> >> > +
>> >> > +/*
>> >> > + * The EFI stub has its own symbol namespace prefixed by __efistub_, to
>> >> > + * isolate it from the kernel proper. The following symbols are legally
>> >> > + * accessed by the stub, so provide some aliases to make them accessible.
>> >> > + * Only include data symbols here, or text symbols of functions that are
>> >> > + * guaranteed to be safe when executed at another offset than they were
>> >> > + * linked at. The routines below are all implemented in assembler in a
>> >> > + * position independent manner
>> >> > + */
>> >> > +__efistub_memcmp = __pi_memcmp;
>> >> > +__efistub_memchr = __pi_memchr;
>> >> > +__efistub_memcpy = __pi_memcpy;
>> >> > +__efistub_memmove = __pi_memmove;
>> >> > +__efistub_memset = __pi_memset;
>> >> > +__efistub_strlen = __pi_strlen;
>> >> > +__efistub_strcmp = __pi_strcmp;
>> >> > +__efistub_strncmp = __pi_strncmp;
>> >> > +__efistub___flush_dcache_area = __pi___flush_dcache_area;
>> >>
>> >> So why we need these __pi_* aliases?
>> >> We could just do __efistub_memcmp = memcmp; Right?
>> >
>> > We *could*, but that defeats the whole purpose of tagging
>> > position-independent functions explicitly in the kernel text.
>> >
>>
>> I just don't get that "the whole purpose of tagging".
>>
>> Yes, the EFI stub is allowed to call only PI kernel functions.
>> But the EFI stub already protected by __efistub_ namespace.
>> If we want to use some new PI function in the stub, we would need add
>> it into this list at first.
>> So that __pi_ namespace doesn't bring any protection or isolation.
>
> What it does it force people making future changes to the __pi_* functions
> to think about the stub, otherwise if the function happens to be
> position-independent when efistub starts using it, it could easily break
> due to some future patch where the author didn't realise that it was
> being used in that manner.
>
That makes sense, thanks.
> Will
^ permalink raw reply [flat|nested] 46+ messages in thread
* [PATCH v4 3/3] arm64/efi: isolate EFI stub from the kernel proper
@ 2015-10-09 9:48 ` Andrey Ryabinin
0 siblings, 0 replies; 46+ messages in thread
From: Andrey Ryabinin @ 2015-10-09 9:48 UTC (permalink / raw)
To: linux-arm-kernel
2015-10-09 12:43 GMT+03:00 Will Deacon <will.deacon@arm.com>:
> On Fri, Oct 09, 2015 at 12:40:21PM +0300, Andrey Ryabinin wrote:
>> 2015-10-09 12:10 GMT+03:00 Will Deacon <will.deacon@arm.com>:
>> > On Fri, Oct 09, 2015 at 11:12:24AM +0300, Andrey Ryabinin wrote:
>> >> 2015-10-08 22:02 GMT+03:00 Ard Biesheuvel <ard.biesheuvel@linaro.org>:
>> >> > --- a/arch/arm64/kernel/image.h
>> >> > +++ b/arch/arm64/kernel/image.h
>> >> > @@ -59,4 +59,31 @@
>> >> > _kernel_offset_le = DATA_LE64(TEXT_OFFSET); \
>> >> > _kernel_flags_le = DATA_LE64(__HEAD_FLAGS);
>> >> >
>> >> > +#ifdef CONFIG_EFI
>> >> > +
>> >> > +/*
>> >> > + * The EFI stub has its own symbol namespace prefixed by __efistub_, to
>> >> > + * isolate it from the kernel proper. The following symbols are legally
>> >> > + * accessed by the stub, so provide some aliases to make them accessible.
>> >> > + * Only include data symbols here, or text symbols of functions that are
>> >> > + * guaranteed to be safe when executed at another offset than they were
>> >> > + * linked at. The routines below are all implemented in assembler in a
>> >> > + * position independent manner
>> >> > + */
>> >> > +__efistub_memcmp = __pi_memcmp;
>> >> > +__efistub_memchr = __pi_memchr;
>> >> > +__efistub_memcpy = __pi_memcpy;
>> >> > +__efistub_memmove = __pi_memmove;
>> >> > +__efistub_memset = __pi_memset;
>> >> > +__efistub_strlen = __pi_strlen;
>> >> > +__efistub_strcmp = __pi_strcmp;
>> >> > +__efistub_strncmp = __pi_strncmp;
>> >> > +__efistub___flush_dcache_area = __pi___flush_dcache_area;
>> >>
>> >> So why we need these __pi_* aliases?
>> >> We could just do __efistub_memcmp = memcmp; Right?
>> >
>> > We *could*, but that defeats the whole purpose of tagging
>> > position-independent functions explicitly in the kernel text.
>> >
>>
>> I just don't get that "the whole purpose of tagging".
>>
>> Yes, the EFI stub is allowed to call only PI kernel functions.
>> But the EFI stub already protected by __efistub_ namespace.
>> If we want to use some new PI function in the stub, we would need add
>> it into this list at first.
>> So that __pi_ namespace doesn't bring any protection or isolation.
>
> What it does it force people making future changes to the __pi_* functions
> to think about the stub, otherwise if the function happens to be
> position-independent when efistub starts using it, it could easily break
> due to some future patch where the author didn't realise that it was
> being used in that manner.
>
That makes sense, thanks.
> Will
^ permalink raw reply [flat|nested] 46+ messages in thread
* Re: [PATCH v4 1/3] arm64/efi: remove /chosen/linux,uefi-stub-kern-ver DT property
2015-10-08 19:02 ` [PATCH v4 1/3] arm64/efi: remove /chosen/linux, uefi-stub-kern-ver " Ard Biesheuvel
@ 2015-10-10 22:31 ` Matt Fleming
-1 siblings, 0 replies; 46+ messages in thread
From: Matt Fleming @ 2015-10-10 22:31 UTC (permalink / raw)
To: Ard Biesheuvel
Cc: linux-efi-u79uwXL29TY76Z2rM5mHXA,
linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r,
matt.fleming-ral2JQCrhuEAvxtiuMwx3w, mark.rutland-5wv7dgnIgG8,
catalin.marinas-5wv7dgnIgG8, will.deacon-5wv7dgnIgG8,
leif.lindholm-QSEj5FYQhm4dnm+yROfE0A,
ryabinin.a.a-Re5JQEeQqe8AvxtiuMwx3w
On Thu, 08 Oct, at 08:02:02PM, Ard Biesheuvel wrote:
> With the stub to kernel interface being promoted to a proper interface
> so that other agents than the stub can boot the kernel proper in EFI
> mode, we can remove the linux,uefi-stub-kern-ver field, considering
> that its original purpose was to prevent this from happening in the
> first place.
>
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
> ---
> Documentation/arm/uefi.txt | 2 --
> drivers/firmware/efi/libstub/fdt.c | 9 ---------
> 2 files changed, 11 deletions(-)
Good riddance ;-)
Reviewed-by: Matt Fleming <matt.fleming-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
--
Matt Fleming, Intel Open Source Technology Center
^ permalink raw reply [flat|nested] 46+ messages in thread
* [PATCH v4 1/3] arm64/efi: remove /chosen/linux,uefi-stub-kern-ver DT property
@ 2015-10-10 22:31 ` Matt Fleming
0 siblings, 0 replies; 46+ messages in thread
From: Matt Fleming @ 2015-10-10 22:31 UTC (permalink / raw)
To: linux-arm-kernel
On Thu, 08 Oct, at 08:02:02PM, Ard Biesheuvel wrote:
> With the stub to kernel interface being promoted to a proper interface
> so that other agents than the stub can boot the kernel proper in EFI
> mode, we can remove the linux,uefi-stub-kern-ver field, considering
> that its original purpose was to prevent this from happening in the
> first place.
>
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> ---
> Documentation/arm/uefi.txt | 2 --
> drivers/firmware/efi/libstub/fdt.c | 9 ---------
> 2 files changed, 11 deletions(-)
Good riddance ;-)
Reviewed-by: Matt Fleming <matt.fleming@intel.com>
--
Matt Fleming, Intel Open Source Technology Center
^ permalink raw reply [flat|nested] 46+ messages in thread
* Re: [PATCH v4 3/3] arm64/efi: isolate EFI stub from the kernel proper
2015-10-08 19:02 ` Ard Biesheuvel
@ 2015-10-10 22:40 ` Matt Fleming
-1 siblings, 0 replies; 46+ messages in thread
From: Matt Fleming @ 2015-10-10 22:40 UTC (permalink / raw)
To: Ard Biesheuvel
Cc: linux-efi-u79uwXL29TY76Z2rM5mHXA,
linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r,
matt.fleming-ral2JQCrhuEAvxtiuMwx3w, mark.rutland-5wv7dgnIgG8,
catalin.marinas-5wv7dgnIgG8, will.deacon-5wv7dgnIgG8,
leif.lindholm-QSEj5FYQhm4dnm+yROfE0A,
ryabinin.a.a-Re5JQEeQqe8AvxtiuMwx3w
On Thu, 08 Oct, at 08:02:04PM, Ard Biesheuvel wrote:
> Since arm64 does not use a builtin decompressor, the EFI stub is built
> into the kernel proper. So far, this has been working fine, but actually,
> since the stub is in fact a PE/COFF relocatable binary that is executed
> at an unknown offset in the 1:1 mapping provided by the UEFI firmware, we
> should not be seamlessly sharing code with the kernel proper, which is a
> position dependent executable linked at a high virtual offset.
>
> So instead, separate the contents of libstub and its dependencies, by
> putting them into their own namespace by prefixing all of its symbols
> with __efistub. This way, we have tight control over what parts of the
> kernel proper are referenced by the stub.
>
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
> ---
> arch/arm64/kernel/Makefile | 12 ++++-
> arch/arm64/kernel/efi-entry.S | 10 ++--
> arch/arm64/kernel/head.S | 14 ++---
> arch/arm64/kernel/image.h | 27 ++++++++++
> drivers/firmware/efi/libstub/Makefile | 39 +++++++++++---
> drivers/firmware/efi/libstub/string.c | 57 ++++++++++++++++++++
> 6 files changed, 139 insertions(+), 20 deletions(-)
Reviewed-by: Matt Fleming <matt.fleming-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
--
Matt Fleming, Intel Open Source Technology Center
^ permalink raw reply [flat|nested] 46+ messages in thread
* [PATCH v4 3/3] arm64/efi: isolate EFI stub from the kernel proper
@ 2015-10-10 22:40 ` Matt Fleming
0 siblings, 0 replies; 46+ messages in thread
From: Matt Fleming @ 2015-10-10 22:40 UTC (permalink / raw)
To: linux-arm-kernel
On Thu, 08 Oct, at 08:02:04PM, Ard Biesheuvel wrote:
> Since arm64 does not use a builtin decompressor, the EFI stub is built
> into the kernel proper. So far, this has been working fine, but actually,
> since the stub is in fact a PE/COFF relocatable binary that is executed
> at an unknown offset in the 1:1 mapping provided by the UEFI firmware, we
> should not be seamlessly sharing code with the kernel proper, which is a
> position dependent executable linked at a high virtual offset.
>
> So instead, separate the contents of libstub and its dependencies, by
> putting them into their own namespace by prefixing all of its symbols
> with __efistub. This way, we have tight control over what parts of the
> kernel proper are referenced by the stub.
>
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> ---
> arch/arm64/kernel/Makefile | 12 ++++-
> arch/arm64/kernel/efi-entry.S | 10 ++--
> arch/arm64/kernel/head.S | 14 ++---
> arch/arm64/kernel/image.h | 27 ++++++++++
> drivers/firmware/efi/libstub/Makefile | 39 +++++++++++---
> drivers/firmware/efi/libstub/string.c | 57 ++++++++++++++++++++
> 6 files changed, 139 insertions(+), 20 deletions(-)
Reviewed-by: Matt Fleming <matt.fleming@intel.com>
--
Matt Fleming, Intel Open Source Technology Center
^ permalink raw reply [flat|nested] 46+ messages in thread
* Re: [PATCH v4 0/3] arm64: EFI stub isolation
2015-10-08 19:02 ` Ard Biesheuvel
@ 2015-10-10 22:40 ` Matt Fleming
-1 siblings, 0 replies; 46+ messages in thread
From: Matt Fleming @ 2015-10-10 22:40 UTC (permalink / raw)
To: Ard Biesheuvel
Cc: linux-efi-u79uwXL29TY76Z2rM5mHXA,
linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r,
matt.fleming-ral2JQCrhuEAvxtiuMwx3w, mark.rutland-5wv7dgnIgG8,
catalin.marinas-5wv7dgnIgG8, will.deacon-5wv7dgnIgG8,
leif.lindholm-QSEj5FYQhm4dnm+yROfE0A,
ryabinin.a.a-Re5JQEeQqe8AvxtiuMwx3w
On Thu, 08 Oct, at 08:02:01PM, Ard Biesheuvel wrote:
> We need to ensure that the EFI stub only uses parts of the kernel proper
> that are safe to use when the kernel virtual mapping is not active yet.
>
> So move all C code dependencies to the libstub, which is built with all
> instrumentation (gcov, kasan) disabled, and do a verification pass to
> ensure that no absolute relocations are used.
>
> On the arm64 side, annotate all the stub's dependencies as safe for PI
> (position independent
>
> @Matt: if you are OK with these, may we please have your ack on patches #1 and
> #2 so that Catalin can pick up the series? Thanks.
I assumed you meant PATCH 1 and PATCH 3. If so, yeah, these look fine
to be taken through Catalin's tree.
--
Matt Fleming, Intel Open Source Technology Center
^ permalink raw reply [flat|nested] 46+ messages in thread
* [PATCH v4 0/3] arm64: EFI stub isolation
@ 2015-10-10 22:40 ` Matt Fleming
0 siblings, 0 replies; 46+ messages in thread
From: Matt Fleming @ 2015-10-10 22:40 UTC (permalink / raw)
To: linux-arm-kernel
On Thu, 08 Oct, at 08:02:01PM, Ard Biesheuvel wrote:
> We need to ensure that the EFI stub only uses parts of the kernel proper
> that are safe to use when the kernel virtual mapping is not active yet.
>
> So move all C code dependencies to the libstub, which is built with all
> instrumentation (gcov, kasan) disabled, and do a verification pass to
> ensure that no absolute relocations are used.
>
> On the arm64 side, annotate all the stub's dependencies as safe for PI
> (position independent
>
> @Matt: if you are OK with these, may we please have your ack on patches #1 and
> #2 so that Catalin can pick up the series? Thanks.
I assumed you meant PATCH 1 and PATCH 3. If so, yeah, these look fine
to be taken through Catalin's tree.
--
Matt Fleming, Intel Open Source Technology Center
^ permalink raw reply [flat|nested] 46+ messages in thread
* Re: [PATCH v4 0/3] arm64: EFI stub isolation
2015-10-10 22:40 ` Matt Fleming
@ 2015-10-12 15:30 ` Catalin Marinas
-1 siblings, 0 replies; 46+ messages in thread
From: Catalin Marinas @ 2015-10-12 15:30 UTC (permalink / raw)
To: Matt Fleming
Cc: Ard Biesheuvel, mark.rutland-5wv7dgnIgG8,
linux-efi-u79uwXL29TY76Z2rM5mHXA,
ryabinin.a.a-Re5JQEeQqe8AvxtiuMwx3w, will.deacon-5wv7dgnIgG8,
leif.lindholm-QSEj5FYQhm4dnm+yROfE0A,
matt.fleming-ral2JQCrhuEAvxtiuMwx3w,
linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r
On Sat, Oct 10, 2015 at 11:40:51PM +0100, Matt Fleming wrote:
> On Thu, 08 Oct, at 08:02:01PM, Ard Biesheuvel wrote:
> > We need to ensure that the EFI stub only uses parts of the kernel proper
> > that are safe to use when the kernel virtual mapping is not active yet.
> >
> > So move all C code dependencies to the libstub, which is built with all
> > instrumentation (gcov, kasan) disabled, and do a verification pass to
> > ensure that no absolute relocations are used.
> >
> > On the arm64 side, annotate all the stub's dependencies as safe for PI
> > (position independent
> >
> > @Matt: if you are OK with these, may we please have your ack on patches #1 and
> > #2 so that Catalin can pick up the series? Thanks.
>
> I assumed you meant PATCH 1 and PATCH 3. If so, yeah, these look fine
> to be taken through Catalin's tree.
Thanks for the review. Patches queued for 4.4.
--
Catalin
^ permalink raw reply [flat|nested] 46+ messages in thread
* [PATCH v4 0/3] arm64: EFI stub isolation
@ 2015-10-12 15:30 ` Catalin Marinas
0 siblings, 0 replies; 46+ messages in thread
From: Catalin Marinas @ 2015-10-12 15:30 UTC (permalink / raw)
To: linux-arm-kernel
On Sat, Oct 10, 2015 at 11:40:51PM +0100, Matt Fleming wrote:
> On Thu, 08 Oct, at 08:02:01PM, Ard Biesheuvel wrote:
> > We need to ensure that the EFI stub only uses parts of the kernel proper
> > that are safe to use when the kernel virtual mapping is not active yet.
> >
> > So move all C code dependencies to the libstub, which is built with all
> > instrumentation (gcov, kasan) disabled, and do a verification pass to
> > ensure that no absolute relocations are used.
> >
> > On the arm64 side, annotate all the stub's dependencies as safe for PI
> > (position independent
> >
> > @Matt: if you are OK with these, may we please have your ack on patches #1 and
> > #2 so that Catalin can pick up the series? Thanks.
>
> I assumed you meant PATCH 1 and PATCH 3. If so, yeah, these look fine
> to be taken through Catalin's tree.
Thanks for the review. Patches queued for 4.4.
--
Catalin
^ permalink raw reply [flat|nested] 46+ messages in thread
* Re: [PATCH v4 3/3] arm64/efi: isolate EFI stub from the kernel proper
2015-10-08 19:02 ` Ard Biesheuvel
@ 2015-10-26 22:26 ` Jeremy Linton
-1 siblings, 0 replies; 46+ messages in thread
From: Jeremy Linton @ 2015-10-26 22:26 UTC (permalink / raw)
To: Ard Biesheuvel, linux-efi-u79uwXL29TY76Z2rM5mHXA,
linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r,
matt.fleming-ral2JQCrhuEAvxtiuMwx3w, mark.rutland-5wv7dgnIgG8,
catalin.marinas-5wv7dgnIgG8, will.deacon-5wv7dgnIgG8,
leif.lindholm-QSEj5FYQhm4dnm+yROfE0A
Cc: ryabinin.a.a-Re5JQEeQqe8AvxtiuMwx3w
On 10/08/2015 02:02 PM, Ard Biesheuvel wrote:
> Since arm64 does not use a builtin decompressor, the EFI stub is built
> into the kernel proper. So far, this has been working fine, but actually,
> since the stub is in fact a PE/COFF relocatable binary that is executed
> at an unknown offset in the 1:1 mapping provided by the UEFI firmware, we
> should not be seamlessly sharing code with the kernel proper, which is a
> position dependent executable linked at a high virtual offset.
This patch appears to be causing a build break
STUBCPY drivers/firmware/efi/libstub/lib-sort.stub.o
0000000000000000 R_AARCH64_ABS64 __efistub___crc_sort
drivers/firmware/efi/libstub/lib-sort.stub.o: absolute symbol references
not allowed in the EFI stub
__kcrctab_sort:
.xword __crc_sort
.weak __crc_sort
.text
Which is the EXPORT_SYMBOL() in sort.c combined with !CONFIG_MODVERSIONS.
^ permalink raw reply [flat|nested] 46+ messages in thread
* [PATCH v4 3/3] arm64/efi: isolate EFI stub from the kernel proper
@ 2015-10-26 22:26 ` Jeremy Linton
0 siblings, 0 replies; 46+ messages in thread
From: Jeremy Linton @ 2015-10-26 22:26 UTC (permalink / raw)
To: linux-arm-kernel
On 10/08/2015 02:02 PM, Ard Biesheuvel wrote:
> Since arm64 does not use a builtin decompressor, the EFI stub is built
> into the kernel proper. So far, this has been working fine, but actually,
> since the stub is in fact a PE/COFF relocatable binary that is executed
> at an unknown offset in the 1:1 mapping provided by the UEFI firmware, we
> should not be seamlessly sharing code with the kernel proper, which is a
> position dependent executable linked at a high virtual offset.
This patch appears to be causing a build break
STUBCPY drivers/firmware/efi/libstub/lib-sort.stub.o
0000000000000000 R_AARCH64_ABS64 __efistub___crc_sort
drivers/firmware/efi/libstub/lib-sort.stub.o: absolute symbol references
not allowed in the EFI stub
__kcrctab_sort:
.xword __crc_sort
.weak __crc_sort
.text
Which is the EXPORT_SYMBOL() in sort.c combined with !CONFIG_MODVERSIONS.
^ permalink raw reply [flat|nested] 46+ messages in thread
* Re: [PATCH v4 3/3] arm64/efi: isolate EFI stub from the kernel proper
2015-10-26 22:26 ` Jeremy Linton
@ 2015-10-26 22:33 ` Jeremy Linton
-1 siblings, 0 replies; 46+ messages in thread
From: Jeremy Linton @ 2015-10-26 22:33 UTC (permalink / raw)
To: Ard Biesheuvel, linux-efi-u79uwXL29TY76Z2rM5mHXA,
linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r,
matt.fleming-ral2JQCrhuEAvxtiuMwx3w, mark.rutland-5wv7dgnIgG8,
catalin.marinas-5wv7dgnIgG8, will.deacon-5wv7dgnIgG8,
leif.lindholm-QSEj5FYQhm4dnm+yROfE0A
Cc: ryabinin.a.a-Re5JQEeQqe8AvxtiuMwx3w
On 10/26/2015 05:26 PM, Jeremy Linton wrote:
> On 10/08/2015 02:02 PM, Ard Biesheuvel wrote:
>> Since arm64 does not use a builtin decompressor, the EFI stub is built
>> into the kernel proper. So far, this has been working fine, but actually,
>> since the stub is in fact a PE/COFF relocatable binary that is executed
>> at an unknown offset in the 1:1 mapping provided by the UEFI firmware, we
>> should not be seamlessly sharing code with the kernel proper, which is a
>> position dependent executable linked at a high virtual offset.
>
> This patch appears to be causing a build break
>
> STUBCPY drivers/firmware/efi/libstub/lib-sort.stub.o
> 0000000000000000 R_AARCH64_ABS64 __efistub___crc_sort
> drivers/firmware/efi/libstub/lib-sort.stub.o: absolute symbol references
> not allowed in the EFI stub
>
> __kcrctab_sort:
> .xword __crc_sort
> .weak __crc_sort
> .text
>
>
> Which is the EXPORT_SYMBOL() in sort.c combined with !CONFIG_MODVERSIONS.
Sorry, I that should be CONFIG_MODVERSIONS..
^ permalink raw reply [flat|nested] 46+ messages in thread
* [PATCH v4 3/3] arm64/efi: isolate EFI stub from the kernel proper
@ 2015-10-26 22:33 ` Jeremy Linton
0 siblings, 0 replies; 46+ messages in thread
From: Jeremy Linton @ 2015-10-26 22:33 UTC (permalink / raw)
To: linux-arm-kernel
On 10/26/2015 05:26 PM, Jeremy Linton wrote:
> On 10/08/2015 02:02 PM, Ard Biesheuvel wrote:
>> Since arm64 does not use a builtin decompressor, the EFI stub is built
>> into the kernel proper. So far, this has been working fine, but actually,
>> since the stub is in fact a PE/COFF relocatable binary that is executed
>> at an unknown offset in the 1:1 mapping provided by the UEFI firmware, we
>> should not be seamlessly sharing code with the kernel proper, which is a
>> position dependent executable linked at a high virtual offset.
>
> This patch appears to be causing a build break
>
> STUBCPY drivers/firmware/efi/libstub/lib-sort.stub.o
> 0000000000000000 R_AARCH64_ABS64 __efistub___crc_sort
> drivers/firmware/efi/libstub/lib-sort.stub.o: absolute symbol references
> not allowed in the EFI stub
>
> __kcrctab_sort:
> .xword __crc_sort
> .weak __crc_sort
> .text
>
>
> Which is the EXPORT_SYMBOL() in sort.c combined with !CONFIG_MODVERSIONS.
Sorry, I that should be CONFIG_MODVERSIONS..
^ permalink raw reply [flat|nested] 46+ messages in thread
* Re: [PATCH v4 3/3] arm64/efi: isolate EFI stub from the kernel proper
2015-10-26 22:33 ` Jeremy Linton
@ 2015-10-27 2:20 ` Ard Biesheuvel
-1 siblings, 0 replies; 46+ messages in thread
From: Ard Biesheuvel @ 2015-10-27 2:20 UTC (permalink / raw)
To: Jeremy Linton
Cc: linux-efi-u79uwXL29TY76Z2rM5mHXA,
linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r, Matt Fleming,
Mark Rutland, Catalin Marinas, Will Deacon, Leif Lindholm,
Andrey Ryabinin
On 27 October 2015 at 07:33, Jeremy Linton <jeremy.linton-5wv7dgnIgG8@public.gmane.org> wrote:
> On 10/26/2015 05:26 PM, Jeremy Linton wrote:
>>
>> On 10/08/2015 02:02 PM, Ard Biesheuvel wrote:
>>>
>>> Since arm64 does not use a builtin decompressor, the EFI stub is built
>>> into the kernel proper. So far, this has been working fine, but actually,
>>> since the stub is in fact a PE/COFF relocatable binary that is executed
>>> at an unknown offset in the 1:1 mapping provided by the UEFI firmware, we
>>> should not be seamlessly sharing code with the kernel proper, which is a
>>> position dependent executable linked at a high virtual offset.
>>
>>
>> This patch appears to be causing a build break
>>
>> STUBCPY drivers/firmware/efi/libstub/lib-sort.stub.o
>> 0000000000000000 R_AARCH64_ABS64 __efistub___crc_sort
>> drivers/firmware/efi/libstub/lib-sort.stub.o: absolute symbol references
>> not allowed in the EFI stub
>>
>> __kcrctab_sort:
>> .xword __crc_sort
>> .weak __crc_sort
>> .text
>>
>>
>> Which is the EXPORT_SYMBOL() in sort.c combined with !CONFIG_MODVERSIONS.
>
>
> Sorry, I that should be CONFIG_MODVERSIONS..
>
Hi Jeremy,
Thanks for the report. The following patch should fix it
-----------------8<----------------
>From 1179099f89db54294f419493d152083fb8e5af3d Mon Sep 17 00:00:00 2001
From: Ard Biesheuvel <ard.biesheuvel-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
Date: Tue, 27 Oct 2015 11:12:51 +0900
Subject: [PATCH] arm64/efi: fix libstub build under CONFIG_MODVERSIONS
Now that we strictly forbid absolute relocations in libstub code,
make sure that we don't emit any when CONFIG_MODVERSIONS is enabled,
by stripping the kcrctab sections from the object file. This fixes
a build problem under CONFIG_MODVERSIONS=y.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
---
drivers/firmware/efi/libstub/Makefile | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/firmware/efi/libstub/Makefile
b/drivers/firmware/efi/libstub/Makefile
index bca9a76cbd33..acc25d7c5da2 100644
--- a/drivers/firmware/efi/libstub/Makefile
+++ b/drivers/firmware/efi/libstub/Makefile
@@ -51,7 +51,7 @@ lib-$(CONFIG_EFI_ARMSTUB) += arm-stub.o fdt.o string.o \
extra-$(CONFIG_EFI_ARMSTUB) := $(lib-y)
lib-$(CONFIG_EFI_ARMSTUB) := $(patsubst %.o,%.stub.o,$(lib-y))
-STUBCOPY_FLAGS-y := -R .debug* -R *ksymtab*
+STUBCOPY_FLAGS-y := -R .debug* -R *ksymtab* -R *kcrctab*
STUBCOPY_FLAGS-$(CONFIG_ARM64) += --prefix-alloc-sections=.init \
--prefix-symbols=__efistub_
STUBCOPY_RELOC-$(CONFIG_ARM64) := R_AARCH64_ABS
--
2.1.4
^ permalink raw reply related [flat|nested] 46+ messages in thread
* [PATCH v4 3/3] arm64/efi: isolate EFI stub from the kernel proper
@ 2015-10-27 2:20 ` Ard Biesheuvel
0 siblings, 0 replies; 46+ messages in thread
From: Ard Biesheuvel @ 2015-10-27 2:20 UTC (permalink / raw)
To: linux-arm-kernel
On 27 October 2015 at 07:33, Jeremy Linton <jeremy.linton@arm.com> wrote:
> On 10/26/2015 05:26 PM, Jeremy Linton wrote:
>>
>> On 10/08/2015 02:02 PM, Ard Biesheuvel wrote:
>>>
>>> Since arm64 does not use a builtin decompressor, the EFI stub is built
>>> into the kernel proper. So far, this has been working fine, but actually,
>>> since the stub is in fact a PE/COFF relocatable binary that is executed
>>> at an unknown offset in the 1:1 mapping provided by the UEFI firmware, we
>>> should not be seamlessly sharing code with the kernel proper, which is a
>>> position dependent executable linked at a high virtual offset.
>>
>>
>> This patch appears to be causing a build break
>>
>> STUBCPY drivers/firmware/efi/libstub/lib-sort.stub.o
>> 0000000000000000 R_AARCH64_ABS64 __efistub___crc_sort
>> drivers/firmware/efi/libstub/lib-sort.stub.o: absolute symbol references
>> not allowed in the EFI stub
>>
>> __kcrctab_sort:
>> .xword __crc_sort
>> .weak __crc_sort
>> .text
>>
>>
>> Which is the EXPORT_SYMBOL() in sort.c combined with !CONFIG_MODVERSIONS.
>
>
> Sorry, I that should be CONFIG_MODVERSIONS..
>
Hi Jeremy,
Thanks for the report. The following patch should fix it
-----------------8<----------------
>From 1179099f89db54294f419493d152083fb8e5af3d Mon Sep 17 00:00:00 2001
From: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Date: Tue, 27 Oct 2015 11:12:51 +0900
Subject: [PATCH] arm64/efi: fix libstub build under CONFIG_MODVERSIONS
Now that we strictly forbid absolute relocations in libstub code,
make sure that we don't emit any when CONFIG_MODVERSIONS is enabled,
by stripping the kcrctab sections from the object file. This fixes
a build problem under CONFIG_MODVERSIONS=y.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
drivers/firmware/efi/libstub/Makefile | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/firmware/efi/libstub/Makefile
b/drivers/firmware/efi/libstub/Makefile
index bca9a76cbd33..acc25d7c5da2 100644
--- a/drivers/firmware/efi/libstub/Makefile
+++ b/drivers/firmware/efi/libstub/Makefile
@@ -51,7 +51,7 @@ lib-$(CONFIG_EFI_ARMSTUB) += arm-stub.o fdt.o string.o \
extra-$(CONFIG_EFI_ARMSTUB) := $(lib-y)
lib-$(CONFIG_EFI_ARMSTUB) := $(patsubst %.o,%.stub.o,$(lib-y))
-STUBCOPY_FLAGS-y := -R .debug* -R *ksymtab*
+STUBCOPY_FLAGS-y := -R .debug* -R *ksymtab* -R *kcrctab*
STUBCOPY_FLAGS-$(CONFIG_ARM64) += --prefix-alloc-sections=.init \
--prefix-symbols=__efistub_
STUBCOPY_RELOC-$(CONFIG_ARM64) := R_AARCH64_ABS
--
2.1.4
^ permalink raw reply related [flat|nested] 46+ messages in thread
* Re: [PATCH v4 3/3] arm64/efi: isolate EFI stub from the kernel proper
2015-10-27 2:20 ` Ard Biesheuvel
@ 2015-10-27 14:44 ` Jeremy Linton
-1 siblings, 0 replies; 46+ messages in thread
From: Jeremy Linton @ 2015-10-27 14:44 UTC (permalink / raw)
To: Ard Biesheuvel
Cc: linux-efi-u79uwXL29TY76Z2rM5mHXA,
linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r, Matt Fleming,
Mark Rutland, Catalin Marinas, Will Deacon, Leif Lindholm,
Andrey Ryabinin
On 10/26/2015 09:20 PM, Ard Biesheuvel wrote:
> Thanks for the report. The following patch should fix it
Ard,
Thanks, it does fix the build problem...
Now to get the darn thing to boot (not related to this AFAIK).
^ permalink raw reply [flat|nested] 46+ messages in thread
* [PATCH v4 3/3] arm64/efi: isolate EFI stub from the kernel proper
@ 2015-10-27 14:44 ` Jeremy Linton
0 siblings, 0 replies; 46+ messages in thread
From: Jeremy Linton @ 2015-10-27 14:44 UTC (permalink / raw)
To: linux-arm-kernel
On 10/26/2015 09:20 PM, Ard Biesheuvel wrote:
> Thanks for the report. The following patch should fix it
Ard,
Thanks, it does fix the build problem...
Now to get the darn thing to boot (not related to this AFAIK).
^ permalink raw reply [flat|nested] 46+ messages in thread
* Re: [PATCH v4 3/3] arm64/efi: isolate EFI stub from the kernel proper
2015-10-27 14:44 ` Jeremy Linton
@ 2015-10-30 12:17 ` Ard Biesheuvel
-1 siblings, 0 replies; 46+ messages in thread
From: Ard Biesheuvel @ 2015-10-30 12:17 UTC (permalink / raw)
To: Jeremy Linton
Cc: linux-efi-u79uwXL29TY76Z2rM5mHXA,
linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r, Matt Fleming,
Mark Rutland, Catalin Marinas, Will Deacon, Leif Lindholm,
Andrey Ryabinin
On 27 October 2015 at 23:44, Jeremy Linton <jeremy.linton-5wv7dgnIgG8@public.gmane.org> wrote:
> On 10/26/2015 09:20 PM, Ard Biesheuvel wrote:
>>
>> Thanks for the report. The following patch should fix it
>
>
> Ard,
>
> Thanks, it does fix the build problem...
>
> Now to get the darn thing to boot (not related to this AFAIK).
>
Catalin,
Would you like me to resend this as a separate patch?
--
Ard.
^ permalink raw reply [flat|nested] 46+ messages in thread
* [PATCH v4 3/3] arm64/efi: isolate EFI stub from the kernel proper
@ 2015-10-30 12:17 ` Ard Biesheuvel
0 siblings, 0 replies; 46+ messages in thread
From: Ard Biesheuvel @ 2015-10-30 12:17 UTC (permalink / raw)
To: linux-arm-kernel
On 27 October 2015 at 23:44, Jeremy Linton <jeremy.linton@arm.com> wrote:
> On 10/26/2015 09:20 PM, Ard Biesheuvel wrote:
>>
>> Thanks for the report. The following patch should fix it
>
>
> Ard,
>
> Thanks, it does fix the build problem...
>
> Now to get the darn thing to boot (not related to this AFAIK).
>
Catalin,
Would you like me to resend this as a separate patch?
--
Ard.
^ permalink raw reply [flat|nested] 46+ messages in thread
* Re: [PATCH v4 3/3] arm64/efi: isolate EFI stub from the kernel proper
2015-10-30 12:17 ` Ard Biesheuvel
@ 2015-10-30 14:35 ` Mark Rutland
-1 siblings, 0 replies; 46+ messages in thread
From: Mark Rutland @ 2015-10-30 14:35 UTC (permalink / raw)
To: Ard Biesheuvel, Catalin Marinas
Cc: Jeremy Linton, linux-efi-u79uwXL29TY76Z2rM5mHXA,
linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r, Matt Fleming,
Will Deacon, Leif Lindholm, Andrey Ryabinin
[Adding Catalin to the To line]
On Fri, Oct 30, 2015 at 01:17:24PM +0100, Ard Biesheuvel wrote:
> On 27 October 2015 at 23:44, Jeremy Linton <jeremy.linton-5wv7dgnIgG8@public.gmane.org> wrote:
> > On 10/26/2015 09:20 PM, Ard Biesheuvel wrote:
> >>
> >> Thanks for the report. The following patch should fix it
> >
> >
> > Ard,
> >
> > Thanks, it does fix the build problem...
> >
> > Now to get the darn thing to boot (not related to this AFAIK).
> >
>
> Catalin,
>
> Would you like me to resend this as a separate patch?
Ard's referring to the patch in a prior reply [1].
Mark.
[1] http://lists.infradead.org/pipermail/linux-arm-kernel/2015-October/381074.html
^ permalink raw reply [flat|nested] 46+ messages in thread
* [PATCH v4 3/3] arm64/efi: isolate EFI stub from the kernel proper
@ 2015-10-30 14:35 ` Mark Rutland
0 siblings, 0 replies; 46+ messages in thread
From: Mark Rutland @ 2015-10-30 14:35 UTC (permalink / raw)
To: linux-arm-kernel
[Adding Catalin to the To line]
On Fri, Oct 30, 2015 at 01:17:24PM +0100, Ard Biesheuvel wrote:
> On 27 October 2015 at 23:44, Jeremy Linton <jeremy.linton@arm.com> wrote:
> > On 10/26/2015 09:20 PM, Ard Biesheuvel wrote:
> >>
> >> Thanks for the report. The following patch should fix it
> >
> >
> > Ard,
> >
> > Thanks, it does fix the build problem...
> >
> > Now to get the darn thing to boot (not related to this AFAIK).
> >
>
> Catalin,
>
> Would you like me to resend this as a separate patch?
Ard's referring to the patch in a prior reply [1].
Mark.
[1] http://lists.infradead.org/pipermail/linux-arm-kernel/2015-October/381074.html
^ permalink raw reply [flat|nested] 46+ messages in thread
* Re: [PATCH v4 3/3] arm64/efi: isolate EFI stub from the kernel proper
2015-10-30 12:17 ` Ard Biesheuvel
@ 2015-10-30 16:01 ` Catalin Marinas
-1 siblings, 0 replies; 46+ messages in thread
From: Catalin Marinas @ 2015-10-30 16:01 UTC (permalink / raw)
To: Ard Biesheuvel
Cc: Jeremy Linton, Mark Rutland, linux-efi-u79uwXL29TY76Z2rM5mHXA,
Andrey Ryabinin, Will Deacon, Leif Lindholm, Matt Fleming,
linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r
On Fri, Oct 30, 2015 at 01:17:24PM +0100, Ard Biesheuvel wrote:
> On 27 October 2015 at 23:44, Jeremy Linton <jeremy.linton-5wv7dgnIgG8@public.gmane.org> wrote:
> > On 10/26/2015 09:20 PM, Ard Biesheuvel wrote:
> >>
> >> Thanks for the report. The following patch should fix it
> >
> >
> > Ard,
> >
> > Thanks, it does fix the build problem...
> >
> > Now to get the darn thing to boot (not related to this AFAIK).
>
> Would you like me to resend this as a separate patch?
No need to but it would be good to get an Ack from Matt since it touches
drivers/firmware/efi/libstub/Makefile (the patch introducing
STUBCOPY_FLAGS was already acked).
--
Catalin
^ permalink raw reply [flat|nested] 46+ messages in thread
* [PATCH v4 3/3] arm64/efi: isolate EFI stub from the kernel proper
@ 2015-10-30 16:01 ` Catalin Marinas
0 siblings, 0 replies; 46+ messages in thread
From: Catalin Marinas @ 2015-10-30 16:01 UTC (permalink / raw)
To: linux-arm-kernel
On Fri, Oct 30, 2015 at 01:17:24PM +0100, Ard Biesheuvel wrote:
> On 27 October 2015 at 23:44, Jeremy Linton <jeremy.linton@arm.com> wrote:
> > On 10/26/2015 09:20 PM, Ard Biesheuvel wrote:
> >>
> >> Thanks for the report. The following patch should fix it
> >
> >
> > Ard,
> >
> > Thanks, it does fix the build problem...
> >
> > Now to get the darn thing to boot (not related to this AFAIK).
>
> Would you like me to resend this as a separate patch?
No need to but it would be good to get an Ack from Matt since it touches
drivers/firmware/efi/libstub/Makefile (the patch introducing
STUBCOPY_FLAGS was already acked).
--
Catalin
^ permalink raw reply [flat|nested] 46+ messages in thread
* Re: [PATCH v4 3/3] arm64/efi: isolate EFI stub from the kernel proper
2015-10-27 2:20 ` Ard Biesheuvel
@ 2015-11-02 12:49 ` Matt Fleming
-1 siblings, 0 replies; 46+ messages in thread
From: Matt Fleming @ 2015-11-02 12:49 UTC (permalink / raw)
To: Ard Biesheuvel
Cc: Jeremy Linton, linux-efi-u79uwXL29TY76Z2rM5mHXA,
linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r, Mark Rutland,
Catalin Marinas, Will Deacon, Leif Lindholm, Andrey Ryabinin
On Tue, 27 Oct, at 11:20:51AM, Ard Biesheuvel wrote:
> From 1179099f89db54294f419493d152083fb8e5af3d Mon Sep 17 00:00:00 2001
> From: Ard Biesheuvel <ard.biesheuvel-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
> Date: Tue, 27 Oct 2015 11:12:51 +0900
> Subject: [PATCH] arm64/efi: fix libstub build under CONFIG_MODVERSIONS
>
> Now that we strictly forbid absolute relocations in libstub code,
> make sure that we don't emit any when CONFIG_MODVERSIONS is enabled,
> by stripping the kcrctab sections from the object file. This fixes
> a build problem under CONFIG_MODVERSIONS=y.
>
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
> ---
> drivers/firmware/efi/libstub/Makefile | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/firmware/efi/libstub/Makefile
> b/drivers/firmware/efi/libstub/Makefile
> index bca9a76cbd33..acc25d7c5da2 100644
> --- a/drivers/firmware/efi/libstub/Makefile
> +++ b/drivers/firmware/efi/libstub/Makefile
> @@ -51,7 +51,7 @@ lib-$(CONFIG_EFI_ARMSTUB) += arm-stub.o fdt.o string.o \
> extra-$(CONFIG_EFI_ARMSTUB) := $(lib-y)
> lib-$(CONFIG_EFI_ARMSTUB) := $(patsubst %.o,%.stub.o,$(lib-y))
>
> -STUBCOPY_FLAGS-y := -R .debug* -R *ksymtab*
> +STUBCOPY_FLAGS-y := -R .debug* -R *ksymtab* -R *kcrctab*
> STUBCOPY_FLAGS-$(CONFIG_ARM64) += --prefix-alloc-sections=.init \
> --prefix-symbols=__efistub_
> STUBCOPY_RELOC-$(CONFIG_ARM64) := R_AARCH64_ABS
I *think* this should be OK.
Reviewed-by: Matt Fleming <matt-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org>
^ permalink raw reply [flat|nested] 46+ messages in thread
* [PATCH v4 3/3] arm64/efi: isolate EFI stub from the kernel proper
@ 2015-11-02 12:49 ` Matt Fleming
0 siblings, 0 replies; 46+ messages in thread
From: Matt Fleming @ 2015-11-02 12:49 UTC (permalink / raw)
To: linux-arm-kernel
On Tue, 27 Oct, at 11:20:51AM, Ard Biesheuvel wrote:
> From 1179099f89db54294f419493d152083fb8e5af3d Mon Sep 17 00:00:00 2001
> From: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> Date: Tue, 27 Oct 2015 11:12:51 +0900
> Subject: [PATCH] arm64/efi: fix libstub build under CONFIG_MODVERSIONS
>
> Now that we strictly forbid absolute relocations in libstub code,
> make sure that we don't emit any when CONFIG_MODVERSIONS is enabled,
> by stripping the kcrctab sections from the object file. This fixes
> a build problem under CONFIG_MODVERSIONS=y.
>
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> ---
> drivers/firmware/efi/libstub/Makefile | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/firmware/efi/libstub/Makefile
> b/drivers/firmware/efi/libstub/Makefile
> index bca9a76cbd33..acc25d7c5da2 100644
> --- a/drivers/firmware/efi/libstub/Makefile
> +++ b/drivers/firmware/efi/libstub/Makefile
> @@ -51,7 +51,7 @@ lib-$(CONFIG_EFI_ARMSTUB) += arm-stub.o fdt.o string.o \
> extra-$(CONFIG_EFI_ARMSTUB) := $(lib-y)
> lib-$(CONFIG_EFI_ARMSTUB) := $(patsubst %.o,%.stub.o,$(lib-y))
>
> -STUBCOPY_FLAGS-y := -R .debug* -R *ksymtab*
> +STUBCOPY_FLAGS-y := -R .debug* -R *ksymtab* -R *kcrctab*
> STUBCOPY_FLAGS-$(CONFIG_ARM64) += --prefix-alloc-sections=.init \
> --prefix-symbols=__efistub_
> STUBCOPY_RELOC-$(CONFIG_ARM64) := R_AARCH64_ABS
I *think* this should be OK.
Reviewed-by: Matt Fleming <matt@codeblueprint.co.uk>
^ permalink raw reply [flat|nested] 46+ messages in thread
* Re: [PATCH v4 3/3] arm64/efi: isolate EFI stub from the kernel proper
2015-10-08 19:02 ` Ard Biesheuvel
@ 2015-11-24 9:34 ` Robert Richter
-1 siblings, 0 replies; 46+ messages in thread
From: Robert Richter @ 2015-11-24 9:34 UTC (permalink / raw)
To: Ard Biesheuvel
Cc: mark.rutland, linux-efi, ryabinin.a.a, catalin.marinas,
will.deacon, leif.lindholm, matt.fleming, linux-arm-kernel
Ard,
On 08.10.15 20:02:04, Ard Biesheuvel wrote:
> +quiet_cmd_stubcopy = STUBCPY $@
> + cmd_stubcopy = if $(OBJCOPY) $(STUBCOPY_FLAGS-y) $< $@; then \
> + $(OBJDUMP) -r $@ | grep $(STUBCOPY_RELOC-y) \
> + && (echo >&2 "$@: absolute symbol references not allowed in the EFI stub"; \
> + rm -f $@; /bin/false); else /bin/false; fi
This one is causing some more build errors for my setup. Any hint how
to fix that?
Thanks,
-Robert
STUBCPY drivers/firmware/efi/libstub/arm-stub.stub.o
0000000000000006 R_AARCH64_ABS32 .debug_abbrev
000000000000000c R_AARCH64_ABS32 .debug_str+0x0000000000000890
0000000000000011 R_AARCH64_ABS32 .debug_str+0x0000000000004ecd
0000000000000015 R_AARCH64_ABS32 .debug_str+0x0000000000000bb1
0000000000000019 R_AARCH64_ABS64 .init.text
0000000000000021 R_AARCH64_ABS64 .init.text+0x00000000000008cc
0000000000000029 R_AARCH64_ABS32 .debug_line
0000000000000030 R_AARCH64_ABS32 .debug_str+0x00000000000000eb
0000000000000047 R_AARCH64_ABS32 .debug_str+0x0000000000003ca8
0000000000000059 R_AARCH64_ABS32 .debug_str+0x0000000000004798
0000000000000060 R_AARCH64_ABS32 .debug_str+0x0000000000005008
...
000000000000a4bb R_AARCH64_ABS32 .debug_str+0x0000000000004a75
000000000000a4da R_AARCH64_ABS32 .debug_str+0x00000000000029ee
000000000000a4f7 R_AARCH64_ABS32 .debug_str+0x0000000000001d95
000000000000a519 R_AARCH64_ABS32 .debug_str+0x0000000000000773
0000000000000006 R_AARCH64_ABS32 .debug_info
0000000000000010 R_AARCH64_ABS64 .init.text
0000000000000623 R_AARCH64_ABS64 .init.text
0000000000000014 R_AARCH64_ABS32 .debug_frame
0000000000000018 R_AARCH64_ABS64 .init.text
000000000000002c R_AARCH64_ABS32 .debug_frame
0000000000000030 R_AARCH64_ABS64 .init.text+0x0000000000000018
0000000000000074 R_AARCH64_ABS32 .debug_frame
0000000000000078 R_AARCH64_ABS64 .init.text+0x0000000000000140
000000000000009c R_AARCH64_ABS32 .debug_frame
00000000000000a0 R_AARCH64_ABS64 .init.text+0x0000000000000158
00000000000000c4 R_AARCH64_ABS32 .debug_frame
00000000000000c8 R_AARCH64_ABS64 .init.text+0x0000000000000170
000000000000012c R_AARCH64_ABS32 .debug_frame
0000000000000130 R_AARCH64_ABS64 .init.text+0x0000000000000390
0000000000000154 R_AARCH64_ABS32 .debug_frame
0000000000000158 R_AARCH64_ABS64 .init.text+0x00000000000003b0
00000000000001a4 R_AARCH64_ABS32 .debug_frame
00000000000001a8 R_AARCH64_ABS64 .init.text+0x0000000000000780
drivers/firmware/efi/libstub/arm-stub.stub.o: absolute symbol references not allowed in the EFI stub
^ permalink raw reply [flat|nested] 46+ messages in thread
* [PATCH v4 3/3] arm64/efi: isolate EFI stub from the kernel proper
@ 2015-11-24 9:34 ` Robert Richter
0 siblings, 0 replies; 46+ messages in thread
From: Robert Richter @ 2015-11-24 9:34 UTC (permalink / raw)
To: linux-arm-kernel
Ard,
On 08.10.15 20:02:04, Ard Biesheuvel wrote:
> +quiet_cmd_stubcopy = STUBCPY $@
> + cmd_stubcopy = if $(OBJCOPY) $(STUBCOPY_FLAGS-y) $< $@; then \
> + $(OBJDUMP) -r $@ | grep $(STUBCOPY_RELOC-y) \
> + && (echo >&2 "$@: absolute symbol references not allowed in the EFI stub"; \
> + rm -f $@; /bin/false); else /bin/false; fi
This one is causing some more build errors for my setup. Any hint how
to fix that?
Thanks,
-Robert
STUBCPY drivers/firmware/efi/libstub/arm-stub.stub.o
0000000000000006 R_AARCH64_ABS32 .debug_abbrev
000000000000000c R_AARCH64_ABS32 .debug_str+0x0000000000000890
0000000000000011 R_AARCH64_ABS32 .debug_str+0x0000000000004ecd
0000000000000015 R_AARCH64_ABS32 .debug_str+0x0000000000000bb1
0000000000000019 R_AARCH64_ABS64 .init.text
0000000000000021 R_AARCH64_ABS64 .init.text+0x00000000000008cc
0000000000000029 R_AARCH64_ABS32 .debug_line
0000000000000030 R_AARCH64_ABS32 .debug_str+0x00000000000000eb
0000000000000047 R_AARCH64_ABS32 .debug_str+0x0000000000003ca8
0000000000000059 R_AARCH64_ABS32 .debug_str+0x0000000000004798
0000000000000060 R_AARCH64_ABS32 .debug_str+0x0000000000005008
...
000000000000a4bb R_AARCH64_ABS32 .debug_str+0x0000000000004a75
000000000000a4da R_AARCH64_ABS32 .debug_str+0x00000000000029ee
000000000000a4f7 R_AARCH64_ABS32 .debug_str+0x0000000000001d95
000000000000a519 R_AARCH64_ABS32 .debug_str+0x0000000000000773
0000000000000006 R_AARCH64_ABS32 .debug_info
0000000000000010 R_AARCH64_ABS64 .init.text
0000000000000623 R_AARCH64_ABS64 .init.text
0000000000000014 R_AARCH64_ABS32 .debug_frame
0000000000000018 R_AARCH64_ABS64 .init.text
000000000000002c R_AARCH64_ABS32 .debug_frame
0000000000000030 R_AARCH64_ABS64 .init.text+0x0000000000000018
0000000000000074 R_AARCH64_ABS32 .debug_frame
0000000000000078 R_AARCH64_ABS64 .init.text+0x0000000000000140
000000000000009c R_AARCH64_ABS32 .debug_frame
00000000000000a0 R_AARCH64_ABS64 .init.text+0x0000000000000158
00000000000000c4 R_AARCH64_ABS32 .debug_frame
00000000000000c8 R_AARCH64_ABS64 .init.text+0x0000000000000170
000000000000012c R_AARCH64_ABS32 .debug_frame
0000000000000130 R_AARCH64_ABS64 .init.text+0x0000000000000390
0000000000000154 R_AARCH64_ABS32 .debug_frame
0000000000000158 R_AARCH64_ABS64 .init.text+0x00000000000003b0
00000000000001a4 R_AARCH64_ABS32 .debug_frame
00000000000001a8 R_AARCH64_ABS64 .init.text+0x0000000000000780
drivers/firmware/efi/libstub/arm-stub.stub.o: absolute symbol references not allowed in the EFI stub
^ permalink raw reply [flat|nested] 46+ messages in thread
* Re: [PATCH v4 3/3] arm64/efi: isolate EFI stub from the kernel proper
2015-11-24 9:34 ` Robert Richter
@ 2015-11-24 9:38 ` Ard Biesheuvel
-1 siblings, 0 replies; 46+ messages in thread
From: Ard Biesheuvel @ 2015-11-24 9:38 UTC (permalink / raw)
To: Robert Richter
Cc: linux-efi-u79uwXL29TY76Z2rM5mHXA,
linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r, Matt Fleming,
Mark Rutland, Catalin Marinas, Will Deacon, Leif Lindholm,
Andrey Ryabinin
On 24 November 2015 at 10:34, Robert Richter
<robert.richter-M3mlKVOIwJVv6pq1l3V1OdBPR1lH4CV8@public.gmane.org> wrote:
> Ard,
>
> On 08.10.15 20:02:04, Ard Biesheuvel wrote:
>> +quiet_cmd_stubcopy = STUBCPY $@
>> + cmd_stubcopy = if $(OBJCOPY) $(STUBCOPY_FLAGS-y) $< $@; then \
>> + $(OBJDUMP) -r $@ | grep $(STUBCOPY_RELOC-y) \
>> + && (echo >&2 "$@: absolute symbol references not allowed in the EFI stub"; \
>> + rm -f $@; /bin/false); else /bin/false; fi
>
> This one is causing some more build errors for my setup. Any hint how
> to fix that?
>
Did you remove -R .debug* from the STUBCOPY_FLAGS-$(CONFIG_ARM64) line?
The problem here is that
a) .debug contains absolute relocations, which is harmless by itself
since they are not used by the program itself, but
b) the .debug sections also contain references to the ksymtab and
kcrctab sections, which should be removed, and removing those and
keeping .debug* sadly doesn't work.
--
Ard.
>
> STUBCPY drivers/firmware/efi/libstub/arm-stub.stub.o
> 0000000000000006 R_AARCH64_ABS32 .debug_abbrev
> 000000000000000c R_AARCH64_ABS32 .debug_str+0x0000000000000890
> 0000000000000011 R_AARCH64_ABS32 .debug_str+0x0000000000004ecd
> 0000000000000015 R_AARCH64_ABS32 .debug_str+0x0000000000000bb1
> 0000000000000019 R_AARCH64_ABS64 .init.text
> 0000000000000021 R_AARCH64_ABS64 .init.text+0x00000000000008cc
> 0000000000000029 R_AARCH64_ABS32 .debug_line
> 0000000000000030 R_AARCH64_ABS32 .debug_str+0x00000000000000eb
> 0000000000000047 R_AARCH64_ABS32 .debug_str+0x0000000000003ca8
> 0000000000000059 R_AARCH64_ABS32 .debug_str+0x0000000000004798
> 0000000000000060 R_AARCH64_ABS32 .debug_str+0x0000000000005008
> ...
> 000000000000a4bb R_AARCH64_ABS32 .debug_str+0x0000000000004a75
> 000000000000a4da R_AARCH64_ABS32 .debug_str+0x00000000000029ee
> 000000000000a4f7 R_AARCH64_ABS32 .debug_str+0x0000000000001d95
> 000000000000a519 R_AARCH64_ABS32 .debug_str+0x0000000000000773
> 0000000000000006 R_AARCH64_ABS32 .debug_info
> 0000000000000010 R_AARCH64_ABS64 .init.text
> 0000000000000623 R_AARCH64_ABS64 .init.text
> 0000000000000014 R_AARCH64_ABS32 .debug_frame
> 0000000000000018 R_AARCH64_ABS64 .init.text
> 000000000000002c R_AARCH64_ABS32 .debug_frame
> 0000000000000030 R_AARCH64_ABS64 .init.text+0x0000000000000018
> 0000000000000074 R_AARCH64_ABS32 .debug_frame
> 0000000000000078 R_AARCH64_ABS64 .init.text+0x0000000000000140
> 000000000000009c R_AARCH64_ABS32 .debug_frame
> 00000000000000a0 R_AARCH64_ABS64 .init.text+0x0000000000000158
> 00000000000000c4 R_AARCH64_ABS32 .debug_frame
> 00000000000000c8 R_AARCH64_ABS64 .init.text+0x0000000000000170
> 000000000000012c R_AARCH64_ABS32 .debug_frame
> 0000000000000130 R_AARCH64_ABS64 .init.text+0x0000000000000390
> 0000000000000154 R_AARCH64_ABS32 .debug_frame
> 0000000000000158 R_AARCH64_ABS64 .init.text+0x00000000000003b0
> 00000000000001a4 R_AARCH64_ABS32 .debug_frame
> 00000000000001a8 R_AARCH64_ABS64 .init.text+0x0000000000000780
> drivers/firmware/efi/libstub/arm-stub.stub.o: absolute symbol references not allowed in the EFI stub
^ permalink raw reply [flat|nested] 46+ messages in thread
* [PATCH v4 3/3] arm64/efi: isolate EFI stub from the kernel proper
@ 2015-11-24 9:38 ` Ard Biesheuvel
0 siblings, 0 replies; 46+ messages in thread
From: Ard Biesheuvel @ 2015-11-24 9:38 UTC (permalink / raw)
To: linux-arm-kernel
On 24 November 2015 at 10:34, Robert Richter
<robert.richter@caviumnetworks.com> wrote:
> Ard,
>
> On 08.10.15 20:02:04, Ard Biesheuvel wrote:
>> +quiet_cmd_stubcopy = STUBCPY $@
>> + cmd_stubcopy = if $(OBJCOPY) $(STUBCOPY_FLAGS-y) $< $@; then \
>> + $(OBJDUMP) -r $@ | grep $(STUBCOPY_RELOC-y) \
>> + && (echo >&2 "$@: absolute symbol references not allowed in the EFI stub"; \
>> + rm -f $@; /bin/false); else /bin/false; fi
>
> This one is causing some more build errors for my setup. Any hint how
> to fix that?
>
Did you remove -R .debug* from the STUBCOPY_FLAGS-$(CONFIG_ARM64) line?
The problem here is that
a) .debug contains absolute relocations, which is harmless by itself
since they are not used by the program itself, but
b) the .debug sections also contain references to the ksymtab and
kcrctab sections, which should be removed, and removing those and
keeping .debug* sadly doesn't work.
--
Ard.
>
> STUBCPY drivers/firmware/efi/libstub/arm-stub.stub.o
> 0000000000000006 R_AARCH64_ABS32 .debug_abbrev
> 000000000000000c R_AARCH64_ABS32 .debug_str+0x0000000000000890
> 0000000000000011 R_AARCH64_ABS32 .debug_str+0x0000000000004ecd
> 0000000000000015 R_AARCH64_ABS32 .debug_str+0x0000000000000bb1
> 0000000000000019 R_AARCH64_ABS64 .init.text
> 0000000000000021 R_AARCH64_ABS64 .init.text+0x00000000000008cc
> 0000000000000029 R_AARCH64_ABS32 .debug_line
> 0000000000000030 R_AARCH64_ABS32 .debug_str+0x00000000000000eb
> 0000000000000047 R_AARCH64_ABS32 .debug_str+0x0000000000003ca8
> 0000000000000059 R_AARCH64_ABS32 .debug_str+0x0000000000004798
> 0000000000000060 R_AARCH64_ABS32 .debug_str+0x0000000000005008
> ...
> 000000000000a4bb R_AARCH64_ABS32 .debug_str+0x0000000000004a75
> 000000000000a4da R_AARCH64_ABS32 .debug_str+0x00000000000029ee
> 000000000000a4f7 R_AARCH64_ABS32 .debug_str+0x0000000000001d95
> 000000000000a519 R_AARCH64_ABS32 .debug_str+0x0000000000000773
> 0000000000000006 R_AARCH64_ABS32 .debug_info
> 0000000000000010 R_AARCH64_ABS64 .init.text
> 0000000000000623 R_AARCH64_ABS64 .init.text
> 0000000000000014 R_AARCH64_ABS32 .debug_frame
> 0000000000000018 R_AARCH64_ABS64 .init.text
> 000000000000002c R_AARCH64_ABS32 .debug_frame
> 0000000000000030 R_AARCH64_ABS64 .init.text+0x0000000000000018
> 0000000000000074 R_AARCH64_ABS32 .debug_frame
> 0000000000000078 R_AARCH64_ABS64 .init.text+0x0000000000000140
> 000000000000009c R_AARCH64_ABS32 .debug_frame
> 00000000000000a0 R_AARCH64_ABS64 .init.text+0x0000000000000158
> 00000000000000c4 R_AARCH64_ABS32 .debug_frame
> 00000000000000c8 R_AARCH64_ABS64 .init.text+0x0000000000000170
> 000000000000012c R_AARCH64_ABS32 .debug_frame
> 0000000000000130 R_AARCH64_ABS64 .init.text+0x0000000000000390
> 0000000000000154 R_AARCH64_ABS32 .debug_frame
> 0000000000000158 R_AARCH64_ABS64 .init.text+0x00000000000003b0
> 00000000000001a4 R_AARCH64_ABS32 .debug_frame
> 00000000000001a8 R_AARCH64_ABS64 .init.text+0x0000000000000780
> drivers/firmware/efi/libstub/arm-stub.stub.o: absolute symbol references not allowed in the EFI stub
^ permalink raw reply [flat|nested] 46+ messages in thread
end of thread, other threads:[~2015-11-24 9:38 UTC | newest]
Thread overview: 46+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2015-10-08 19:02 [PATCH v4 0/3] arm64: EFI stub isolation Ard Biesheuvel
2015-10-08 19:02 ` Ard Biesheuvel
[not found] ` <1444330924-17830-1-git-send-email-ard.biesheuvel-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
2015-10-08 19:02 ` [PATCH v4 1/3] arm64/efi: remove /chosen/linux,uefi-stub-kern-ver DT property Ard Biesheuvel
2015-10-08 19:02 ` [PATCH v4 1/3] arm64/efi: remove /chosen/linux, uefi-stub-kern-ver " Ard Biesheuvel
[not found] ` <1444330924-17830-2-git-send-email-ard.biesheuvel-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
2015-10-10 22:31 ` [PATCH v4 1/3] arm64/efi: remove /chosen/linux,uefi-stub-kern-ver " Matt Fleming
2015-10-10 22:31 ` Matt Fleming
2015-10-08 19:02 ` [PATCH v4 2/3] arm64: use ENDPIPROC() to annotate position independent assembler routines Ard Biesheuvel
2015-10-08 19:02 ` Ard Biesheuvel
2015-10-08 19:02 ` [PATCH v4 3/3] arm64/efi: isolate EFI stub from the kernel proper Ard Biesheuvel
2015-10-08 19:02 ` Ard Biesheuvel
[not found] ` <1444330924-17830-4-git-send-email-ard.biesheuvel-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
2015-10-09 8:12 ` Andrey Ryabinin
2015-10-09 8:12 ` Andrey Ryabinin
[not found] ` <CAPAsAGz7Tp6Z87tPq_NNh_mcwPF_DOaXzu0po5f6AQxPAcsALQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2015-10-09 9:10 ` Will Deacon
2015-10-09 9:10 ` Will Deacon
2015-10-09 9:40 ` Andrey Ryabinin
2015-10-09 9:40 ` Andrey Ryabinin
[not found] ` <CAPAsAGzgqOZVdTfpBGADAhZjOJTCqdB1Paq-14vk-_1hu4DCyw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2015-10-09 9:43 ` Will Deacon
2015-10-09 9:43 ` Will Deacon
[not found] ` <20151009094324.GE26278-5wv7dgnIgG8@public.gmane.org>
2015-10-09 9:48 ` Andrey Ryabinin
2015-10-09 9:48 ` Andrey Ryabinin
2015-10-10 22:40 ` Matt Fleming
2015-10-10 22:40 ` Matt Fleming
2015-10-26 22:26 ` Jeremy Linton
2015-10-26 22:26 ` Jeremy Linton
[not found] ` <562EA894.8070505-5wv7dgnIgG8@public.gmane.org>
2015-10-26 22:33 ` Jeremy Linton
2015-10-26 22:33 ` Jeremy Linton
[not found] ` <562EAA22.3010905-5wv7dgnIgG8@public.gmane.org>
2015-10-27 2:20 ` Ard Biesheuvel
2015-10-27 2:20 ` Ard Biesheuvel
[not found] ` <CAKv+Gu-G1YS9Ha=-rtnPKJTOxBTrdSq6=Tqwq_GPW742JUE+2Q-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2015-10-27 14:44 ` Jeremy Linton
2015-10-27 14:44 ` Jeremy Linton
[not found] ` <562F8DCE.4010308-5wv7dgnIgG8@public.gmane.org>
2015-10-30 12:17 ` Ard Biesheuvel
2015-10-30 12:17 ` Ard Biesheuvel
[not found] ` <CAKv+Gu-m7dJbiF=8i=+cN=bx+y8AKu_MgHrS29jNK0fTvuwQ5Q-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2015-10-30 14:35 ` Mark Rutland
2015-10-30 14:35 ` Mark Rutland
2015-10-30 16:01 ` Catalin Marinas
2015-10-30 16:01 ` Catalin Marinas
2015-11-02 12:49 ` Matt Fleming
2015-11-02 12:49 ` Matt Fleming
2015-11-24 9:34 ` Robert Richter
2015-11-24 9:34 ` Robert Richter
[not found] ` <20151124093438.GA31343-vWBEXY7mpu582hYKe6nXyg@public.gmane.org>
2015-11-24 9:38 ` Ard Biesheuvel
2015-11-24 9:38 ` Ard Biesheuvel
2015-10-10 22:40 ` [PATCH v4 0/3] arm64: EFI stub isolation Matt Fleming
2015-10-10 22:40 ` Matt Fleming
[not found] ` <20151010224051.GK2723-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org>
2015-10-12 15:30 ` Catalin Marinas
2015-10-12 15:30 ` Catalin Marinas
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