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Date: Thu, 18 Jul 2013 20:47:53 +0900
From: Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>
To: Ingo Molnar <mingo@...hat.com>, linux-kernel@...r.kernel.org
Cc: "H. Peter Anvin" <hpa@...ux.intel.com>,
Jiri Kosina <jkosina@...e.cz>,
Steven Rostedt <rostedt@...dmis.org>,
Jason Baron <jbaron@...mai.com>, yrl.pp-manager.tt@...achi.com,
Borislav Petkov <bpetkov@...e.de>
Subject: [PATCH -tip 3/3] x86: Remove unused text_poke_smp and
text_poke_smp_batch
Since introducing the text_poke_bp for all text_poke_smp*
callers, text_poke_smp* are now unused. This basically
reverts 3d55cc8a, 7deb18dc and related commits.
This also fixes a Kconfig dependency issue on STOP_MACHINE
in the case of CONFIG_SMP && !CONFIG_MODULE_UNLOAD.
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>
---
arch/x86/Kconfig | 5 --
arch/x86/include/asm/alternative.h | 11 ----
arch/x86/kernel/alternative.c | 98 +-----------------------------------
3 files changed, 2 insertions(+), 112 deletions(-)
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 8dbbdef..9e1e0b6 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -81,7 +81,6 @@ config X86
select HAVE_USER_RETURN_NOTIFIER
select ARCH_BINFMT_ELF_RANDOMIZE_PIE
select HAVE_ARCH_JUMP_LABEL
- select HAVE_TEXT_POKE_SMP
select HAVE_GENERIC_HARDIRQS
select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
select SPARSE_IRQ
@@ -2364,10 +2363,6 @@ config HAVE_ATOMIC_IOMAP
def_bool y
depends on X86_32
-config HAVE_TEXT_POKE_SMP
- bool
- select STOP_MACHINE if SMP
-
config X86_DEV_DMA_OPS
bool
depends on X86_64 || STA2X11
diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index 3abf8dd..4daf8c5 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -220,21 +220,10 @@ extern void *text_poke_early(void *addr, const void *opcode, size_t len);
* no thread can be preempted in the instructions being modified (no iret to an
* invalid instruction possible) or if the instructions are changed from a
* consistent state to another consistent state atomically.
- * More care must be taken when modifying code in the SMP case because of
- * Intel's errata. text_poke_smp() takes care that errata, but still
- * doesn't support NMI/MCE handler code modifying.
* On the local CPU you need to be protected again NMI or MCE handlers seeing an
* inconsistent instruction while you patch.
*/
-struct text_poke_param {
- void *addr;
- const void *opcode;
- size_t len;
-};
-
extern void *text_poke(void *addr, const void *opcode, size_t len);
extern void *text_poke_bp(void *addr, const void *opcode, size_t len, void *handler);
-extern void *text_poke_smp(void *addr, const void *opcode, size_t len);
-extern void text_poke_smp_batch(struct text_poke_param *params, int n);
#endif /* _ASM_X86_ALTERNATIVE_H */
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index 0ab4936..5d8782e 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -633,8 +633,8 @@ static int int3_notify(struct notifier_block *self, unsigned long val, void *dat
* @handler: address to jump to when the temporary breakpoint is hit
*
* Modify multi-byte instruction by using int3 breakpoint on SMP.
- * In contrary to text_poke_smp(), we completely avoid stop_machine() here,
- * and achieve the synchronization using int3 breakpoint.
+ * We completely avoid stop_machine() here, and achieve the
+ * synchronization using int3 breakpoint.
*
* The way it is done:
* - add a int3 trap to the address that will be patched
@@ -702,97 +702,3 @@ static int __init int3_init(void)
}
arch_initcall(int3_init);
-/*
- * Cross-modifying kernel text with stop_machine().
- * This code originally comes from immediate value.
- */
-static atomic_t stop_machine_first;
-static int wrote_text;
-
-struct text_poke_params {
- struct text_poke_param *params;
- int nparams;
-};
-
-static int __kprobes stop_machine_text_poke(void *data)
-{
- struct text_poke_params *tpp = data;
- struct text_poke_param *p;
- int i;
-
- if (atomic_xchg(&stop_machine_first, 0)) {
- for (i = 0; i < tpp->nparams; i++) {
- p = &tpp->params[i];
- text_poke(p->addr, p->opcode, p->len);
- }
- smp_wmb(); /* Make sure other cpus see that this has run */
- wrote_text = 1;
- } else {
- while (!wrote_text)
- cpu_relax();
- smp_mb(); /* Load wrote_text before following execution */
- }
-
- for (i = 0; i < tpp->nparams; i++) {
- p = &tpp->params[i];
- flush_icache_range((unsigned long)p->addr,
- (unsigned long)p->addr + p->len);
- }
- /*
- * Intel Archiecture Software Developer's Manual section 7.1.3 specifies
- * that a core serializing instruction such as "cpuid" should be
- * executed on _each_ core before the new instruction is made visible.
- */
- sync_core();
- return 0;
-}
-
-/**
- * text_poke_smp - Update instructions on a live kernel on SMP
- * @addr: address to modify
- * @opcode: source of the copy
- * @len: length to copy
- *
- * Modify multi-byte instruction by using stop_machine() on SMP. This allows
- * user to poke/set multi-byte text on SMP. Only non-NMI/MCE code modifying
- * should be allowed, since stop_machine() does _not_ protect code against
- * NMI and MCE.
- *
- * Note: Must be called under get_online_cpus() and text_mutex.
- */
-void *__kprobes text_poke_smp(void *addr, const void *opcode, size_t len)
-{
- struct text_poke_params tpp;
- struct text_poke_param p;
-
- p.addr = addr;
- p.opcode = opcode;
- p.len = len;
- tpp.params = &p;
- tpp.nparams = 1;
- atomic_set(&stop_machine_first, 1);
- wrote_text = 0;
- /* Use __stop_machine() because the caller already got online_cpus. */
- __stop_machine(stop_machine_text_poke, (void *)&tpp, cpu_online_mask);
- return addr;
-}
-
-/**
- * text_poke_smp_batch - Update instructions on a live kernel on SMP
- * @params: an array of text_poke parameters
- * @n: the number of elements in params.
- *
- * Modify multi-byte instruction by using stop_machine() on SMP. Since the
- * stop_machine() is heavy task, it is better to aggregate text_poke requests
- * and do it once if possible.
- *
- * Note: Must be called under get_online_cpus() and text_mutex.
- */
-void __kprobes text_poke_smp_batch(struct text_poke_param *params, int n)
-{
- struct text_poke_params tpp = {.params = params, .nparams = n};
-
- atomic_set(&stop_machine_first, 1);
- wrote_text = 0;
- __stop_machine(stop_machine_text_poke, (void *)&tpp, cpu_online_mask);
-}
--
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