From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
To: xen-devel@lists.xenproject.org, ross.lagerwall@citrix.com,
konrad@kernel.org, andrew.cooper3@citrix.com, mpohlack@amazon.de,
sasha.levin@oracle.com
Cc: Keir Fraser <keir@xen.org>, Jan Beulich <jbeulich@suse.com>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Subject: [PATCH v4 24/34] xsplice: Add support for alternatives
Date: Tue, 15 Mar 2016 13:56:46 -0400 [thread overview]
Message-ID: <1458064616-23101-25-git-send-email-konrad.wilk@oracle.com> (raw)
In-Reply-To: <1458064616-23101-1-git-send-email-konrad.wilk@oracle.com>
From: Ross Lagerwall <ross.lagerwall@citrix.com>
Add support for applying alternative sections within xsplice payload.
At payload load time, apply an alternative sections that are found.
Also we add an test-case exercising a rather useless alternative
(patching a NOP with a NOP) - but it does exercise the code-path.
Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
Cc: Keir Fraser <keir@xen.org>
Cc: Jan Beulich <jbeulich@suse.com>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>
v2: Make a new alternative function that does not ASSERT on IRQs and
don't disable IRQs in the code when loading payload.
v3: Include test-case
v4: Include check for size of alternatives and that it is not a 0 size
section.
---
xen/arch/x86/Makefile | 2 +-
xen/arch/x86/alternative.c | 20 ++++++++++++--------
xen/arch/x86/test/xen_hello_world_func.c | 3 +++
xen/common/xsplice.c | 16 ++++++++++++++++
xen/include/asm-x86/alternative.h | 6 ++++++
5 files changed, 38 insertions(+), 9 deletions(-)
diff --git a/xen/arch/x86/Makefile b/xen/arch/x86/Makefile
index a2e3017..8a100be 100644
--- a/xen/arch/x86/Makefile
+++ b/xen/arch/x86/Makefile
@@ -6,7 +6,7 @@ subdir-y += mm
subdir-$(CONFIG_XENOPROF) += oprofile
subdir-y += x86_64
-obj-bin-y += alternative.init.o
+obj-bin-y += alternative.o
obj-y += apic.o
obj-y += bitops.o
obj-bin-y += bzimage.init.o
diff --git a/xen/arch/x86/alternative.c b/xen/arch/x86/alternative.c
index 26ad2b9..e423d3a 100644
--- a/xen/arch/x86/alternative.c
+++ b/xen/arch/x86/alternative.c
@@ -28,7 +28,7 @@
extern struct alt_instr __alt_instructions[], __alt_instructions_end[];
#ifdef K8_NOP1
-static const unsigned char k8nops[] __initconst = {
+static const unsigned char k8nops[] = {
K8_NOP1,
K8_NOP2,
K8_NOP3,
@@ -52,7 +52,7 @@ static const unsigned char * const k8_nops[ASM_NOP_MAX+1] __initconstrel = {
#endif
#ifdef P6_NOP1
-static const unsigned char p6nops[] __initconst = {
+static const unsigned char p6nops[] = {
P6_NOP1,
P6_NOP2,
P6_NOP3,
@@ -75,7 +75,7 @@ static const unsigned char * const p6_nops[ASM_NOP_MAX+1] __initconstrel = {
};
#endif
-static const unsigned char * const *ideal_nops __initdata = k8_nops;
+static const unsigned char * const *ideal_nops = k8_nops;
static int __init mask_nmi_callback(const struct cpu_user_regs *regs, int cpu)
{
@@ -100,7 +100,7 @@ static void __init arch_init_ideal_nops(void)
}
/* Use this to add nops to a buffer, then text_poke the whole buffer. */
-static void __init add_nops(void *insns, unsigned int len)
+static void add_nops(void *insns, unsigned int len)
{
while ( len > 0 )
{
@@ -127,7 +127,7 @@ static void __init add_nops(void *insns, unsigned int len)
*
* This routine is called with local interrupt disabled.
*/
-static void *__init text_poke_early(void *addr, const void *opcode, size_t len)
+static void *text_poke_early(void *addr, const void *opcode, size_t len)
{
memcpy(addr, opcode, len);
sync_core();
@@ -142,15 +142,13 @@ static void *__init text_poke_early(void *addr, const void *opcode, size_t len)
* APs have less capabilities than the boot processor are not handled.
* Tough. Make sure you disable such features by hand.
*/
-static void __init apply_alternatives(struct alt_instr *start, struct alt_instr *end)
+void apply_alternatives_nocheck(struct alt_instr *start, struct alt_instr *end)
{
struct alt_instr *a;
u8 *instr, *replacement;
u8 insnbuf[MAX_PATCH_LEN];
unsigned long cr0 = read_cr0();
- ASSERT(!local_irq_is_enabled());
-
printk(KERN_INFO "alt table %p -> %p\n", start, end);
/* Disable WP to allow application of alternatives to read-only pages. */
@@ -190,6 +188,12 @@ static void __init apply_alternatives(struct alt_instr *start, struct alt_instr
write_cr0(cr0);
}
+void apply_alternatives(struct alt_instr *start, struct alt_instr *end)
+{
+ ASSERT(!local_irq_is_enabled());
+ apply_alternatives_nocheck(start, end);
+}
+
void __init alternative_instructions(void)
{
nmi_callback_t saved_nmi_callback;
diff --git a/xen/arch/x86/test/xen_hello_world_func.c b/xen/arch/x86/test/xen_hello_world_func.c
index 81380a6..2465ce9 100644
--- a/xen/arch/x86/test/xen_hello_world_func.c
+++ b/xen/arch/x86/test/xen_hello_world_func.c
@@ -5,10 +5,13 @@
#include <xen/config.h>
#include <xen/types.h>
+#include <asm/nops.h>
+#include <asm/alternative.h>
/* Our replacement function for xen_extra_version. */
const char *xen_hello_world(void)
{
+ alternative(ASM_NOP1, ASM_NOP1, 1);
return "Hello World";
}
diff --git a/xen/common/xsplice.c b/xen/common/xsplice.c
index 834fda3..e5867bd 100644
--- a/xen/common/xsplice.c
+++ b/xen/common/xsplice.c
@@ -526,8 +526,24 @@ static int prepare_payload(struct payload *payload,
region->ex_end = (struct exception_table_entry *)(sec->load_addr + sec->sec->sh_size);
sort_exception_table(region->ex, region->ex_end);
+
region->priv |= CHECKING_EXCEPTION;
}
+ sec = xsplice_elf_sec_by_name(elf, ".altinstructions");
+ if ( sec )
+ {
+ if ( !sec->sec->sh_size ||
+ (sec->sec->sh_size % sizeof (struct alt_instr)) )
+ {
+ dprintk(XENLOG_DEBUG, "%s%s: Wrong size of .alt_instr (exp:%lu vs %lu)!\n",
+ XSPLICE, elf->name, sizeof (struct alt_instr),
+ sec->sec->sh_size);
+ return -EINVAL;
+ }
+ apply_alternatives_nocheck((struct alt_instr *)sec->load_addr,
+ (struct alt_instr *)(sec->load_addr +
+ sec->sec->sh_size));
+ }
#endif
return 0;
}
diff --git a/xen/include/asm-x86/alternative.h b/xen/include/asm-x86/alternative.h
index 1056630..d50c0b5 100644
--- a/xen/include/asm-x86/alternative.h
+++ b/xen/include/asm-x86/alternative.h
@@ -23,6 +23,12 @@ struct alt_instr {
u8 replacementlen; /* length of new instruction, <= instrlen */
};
+/*
+ * An variant to be used on code that can be patched without many checks.
+ */
+extern void apply_alternatives_nocheck(struct alt_instr *start,
+ struct alt_instr *end);
+extern void apply_alternatives(struct alt_instr *start, struct alt_instr *end);
extern void alternative_instructions(void);
#define OLDINSTR(oldinstr) "661:\n\t" oldinstr "\n662:\n"
--
2.5.0
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next prev parent reply other threads:[~2016-03-15 18:00 UTC|newest]
Thread overview: 124+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-15 17:56 [PATCH v4] xSplice v1 design and implementation Konrad Rzeszutek Wilk
2016-03-15 17:56 ` [PATCH v4 01/34] compat/x86: Remove unncessary #define Konrad Rzeszutek Wilk
2016-03-15 18:57 ` Andrew Cooper
2016-03-16 11:08 ` Jan Beulich
2016-03-17 0:44 ` Konrad Rzeszutek Wilk
2016-03-17 7:45 ` Jan Beulich
2016-03-15 17:56 ` [PATCH v4 02/34] libxc: Remove dead code (XENVER_capabilities) Konrad Rzeszutek Wilk
2016-03-15 18:04 ` Andrew Cooper
2016-03-15 18:08 ` Konrad Rzeszutek Wilk
2016-03-16 18:11 ` Wei Liu
2016-03-15 17:56 ` [PATCH v4 03/34] xsm/xen_version: Add XSM for the xen_version hypercall Konrad Rzeszutek Wilk
2016-03-18 11:55 ` Jan Beulich
2016-03-18 17:26 ` Konrad Rzeszutek Wilk
2016-03-21 11:22 ` Jan Beulich
2016-03-22 16:10 ` Konrad Rzeszutek Wilk
2016-03-22 17:54 ` Daniel De Graaf
2016-03-22 17:49 ` Daniel De Graaf
2016-03-24 15:34 ` anshul makkar
2016-03-24 19:19 ` Konrad Rzeszutek Wilk
2016-03-15 17:56 ` [PATCH v4 04/34] HYPERCALL_version_op. New hypercall mirroring XENVER_ but sane Konrad Rzeszutek Wilk
2016-03-15 18:29 ` Andrew Cooper
2016-03-15 20:19 ` Konrad Rzeszutek Wilk
2016-03-17 1:38 ` Konrad Rzeszutek Wilk
2016-03-17 14:28 ` Andrew Cooper
2016-03-18 12:36 ` Jan Beulich
2016-03-18 19:22 ` Konrad Rzeszutek Wilk
2016-03-21 12:45 ` Jan Beulich
2016-03-22 15:52 ` Konrad Rzeszutek Wilk
2016-03-22 16:06 ` Jan Beulich
2016-03-22 18:57 ` Konrad Rzeszutek Wilk
2016-03-22 19:28 ` Andrew Cooper
2016-03-22 20:39 ` Konrad Rzeszutek Wilk
2016-03-23 8:56 ` Jan Beulich
2016-03-24 2:37 ` Konrad Rzeszutek Wilk
2016-03-24 9:15 ` Jan Beulich
2016-03-24 11:39 ` Konrad Rzeszutek Wilk
2016-03-22 17:51 ` Daniel De Graaf
2016-03-15 17:56 ` [PATCH v4 05/34] libxc/libxl/python/xenstat: Use new XEN_VERSION_OP hypercall Konrad Rzeszutek Wilk
2016-03-15 18:45 ` Andrew Cooper
2016-03-16 12:31 ` George Dunlap
2016-03-16 18:11 ` Wei Liu
2016-03-17 1:08 ` Konrad Rzeszutek Wilk
2016-03-15 17:56 ` [PATCH v4 06/34] x86/arm: Add BUGFRAME_NR define and BUILD checks Konrad Rzeszutek Wilk
2016-03-15 18:54 ` Andrew Cooper
2016-03-16 11:49 ` Julien Grall
2016-03-18 12:40 ` Jan Beulich
2016-03-18 19:59 ` Konrad Rzeszutek Wilk
2016-03-21 12:49 ` Jan Beulich
2016-03-22 15:39 ` Konrad Rzeszutek Wilk
2016-03-22 15:58 ` Jan Beulich
2016-03-15 17:56 ` [PATCH v4 07/34] arm/x86: Use struct virtual_region to do bug, symbol, and (x86) exception tables Konrad Rzeszutek Wilk
2016-03-15 19:24 ` Andrew Cooper
2016-03-15 19:34 ` Konrad Rzeszutek Wilk
2016-03-15 19:51 ` Andrew Cooper
2016-03-15 20:02 ` Andrew Cooper
2016-03-16 10:33 ` Jan Beulich
2016-03-18 13:07 ` Jan Beulich
2016-03-22 20:18 ` Konrad Rzeszutek Wilk
2016-03-23 8:19 ` Jan Beulich
2016-03-23 11:17 ` Julien Grall
2016-03-23 11:21 ` Jan Beulich
2016-03-24 2:49 ` Konrad Rzeszutek Wilk
2016-03-24 9:20 ` Jan Beulich
2016-03-15 17:56 ` [PATCH v4 08/34] vmap: Make the while loop less fishy Konrad Rzeszutek Wilk
2016-03-15 19:33 ` Andrew Cooper
2016-03-17 11:49 ` Jan Beulich
2016-03-17 14:37 ` Andrew Cooper
2016-03-17 15:30 ` Jan Beulich
2016-03-17 16:06 ` Ian Jackson
2016-03-17 11:48 ` Jan Beulich
2016-03-17 16:08 ` Ian Jackson
2016-03-21 12:04 ` George Dunlap
2016-03-21 13:26 ` Jan Beulich
2016-03-21 14:22 ` George Dunlap
2016-03-21 15:05 ` Jan Beulich
2016-03-15 17:56 ` [PATCH v4 09/34] vmap: ASSERT on NULL Konrad Rzeszutek Wilk
2016-03-15 17:56 ` [PATCH v4 10/34] vmap: Add vmalloc_cb and vfree_cb Konrad Rzeszutek Wilk
2016-03-18 13:20 ` Jan Beulich
2016-03-15 17:56 ` [PATCH v4 11/34] xsplice: Design document Konrad Rzeszutek Wilk
2016-03-23 11:18 ` Jan Beulich
2016-03-23 20:12 ` Konrad Rzeszutek Wilk
2016-03-23 20:21 ` Konrad Rzeszutek Wilk
2016-03-24 3:15 ` Konrad Rzeszutek Wilk
2016-03-24 9:32 ` Jan Beulich
2016-03-15 17:56 ` [PATCH v4 12/34] xen/xsplice: Hypervisor implementation of XEN_XSPLICE_op Konrad Rzeszutek Wilk
2016-03-16 12:12 ` Julien Grall
2016-03-16 19:58 ` Konrad Rzeszutek Wilk
2016-03-23 13:51 ` Jan Beulich
2016-03-24 3:13 ` Konrad Rzeszutek Wilk
2016-03-24 9:29 ` Jan Beulich
2016-03-15 17:56 ` [PATCH v4 13/34] libxc: Implementation of XEN_XSPLICE_op in libxc Konrad Rzeszutek Wilk
2016-03-16 18:12 ` Wei Liu
2016-03-16 20:36 ` Konrad Rzeszutek Wilk
2016-03-15 17:56 ` [PATCH v4 14/34] xen-xsplice: Tool to manipulate xsplice payloads Konrad Rzeszutek Wilk
2016-03-16 18:12 ` Wei Liu
2016-03-15 17:56 ` [PATCH v4 15/34] xsplice: Add helper elf routines Konrad Rzeszutek Wilk
2016-03-15 17:56 ` [PATCH v4 16/34] xsplice: Implement payload loading Konrad Rzeszutek Wilk
2016-03-22 17:25 ` Konrad Rzeszutek Wilk
2016-03-15 17:56 ` [PATCH v4 17/34] xsplice: Implement support for applying/reverting/replacing patches Konrad Rzeszutek Wilk
2016-03-15 17:56 ` [PATCH v4 18/34] x86/xen_hello_world.xsplice: Test payload for patching 'xen_extra_version' Konrad Rzeszutek Wilk
2016-03-15 17:56 ` [PATCH v4 19/34] xsplice, symbols: Implement symbol name resolution on address Konrad Rzeszutek Wilk
2016-03-15 17:56 ` [PATCH v4 20/34] x86, xsplice: Print payload's symbol name and payload name in backtraces Konrad Rzeszutek Wilk
2016-03-15 17:56 ` [PATCH v4 21/34] xsplice: Add .xsplice.hooks functions and test-case Konrad Rzeszutek Wilk
2016-03-15 17:56 ` [PATCH v4 22/34] xsplice: Add support for bug frames Konrad Rzeszutek Wilk
2016-03-15 17:56 ` [PATCH v4 23/34] xsplice: Add support for exception tables Konrad Rzeszutek Wilk
2016-03-15 17:56 ` Konrad Rzeszutek Wilk [this message]
2016-03-15 17:56 ` [PATCH v4 25/34] build_id: Provide ld-embedded build-ids Konrad Rzeszutek Wilk
2016-03-16 18:34 ` Julien Grall
2016-03-16 21:02 ` Konrad Rzeszutek Wilk
2016-03-17 1:12 ` Konrad Rzeszutek Wilk
2016-03-17 11:08 ` Julien Grall
2016-03-17 13:39 ` Konrad Rzeszutek Wilk
2016-03-15 17:56 ` [PATCH v4 26/34] HYPERCALL_version_op: Add VERSION_OP_build_id to retrieve build-id Konrad Rzeszutek Wilk
2016-03-15 17:56 ` [PATCH v4 27/34] libxl: info: Display build_id of the hypervisor using XEN_VERSION_OP_build_id Konrad Rzeszutek Wilk
2016-03-16 18:12 ` Wei Liu
2016-03-15 17:56 ` [PATCH v4 28/34] xsplice: Print build_id in keyhandler and on bootup Konrad Rzeszutek Wilk
2016-03-15 17:56 ` [PATCH v4 29/34] xsplice: Stacking build-id dependency checking Konrad Rzeszutek Wilk
2016-03-15 17:56 ` [PATCH v4 30/34] xsplice/xen_replace_world: Test-case for XSPLICE_ACTION_REPLACE Konrad Rzeszutek Wilk
2016-03-15 17:56 ` [PATCH v4 31/34] xsplice: Print dependency and payloads build_id in the keyhandler Konrad Rzeszutek Wilk
2016-03-15 17:56 ` [PATCH v4 32/34] xsplice: Prevent duplicate payloads from being loaded Konrad Rzeszutek Wilk
2016-03-15 17:56 ` [PATCH v4 33/34] xsplice: Add support for shadow variables Konrad Rzeszutek Wilk
2016-03-15 17:56 ` [PATCH v4 34/34] MAINTAINERS/xsplice: Add myself and Ross as the maintainers Konrad Rzeszutek Wilk
2016-03-16 11:10 ` Jan Beulich
2016-03-17 0:44 ` Konrad Rzeszutek Wilk
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