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| author | Masami Hiramatsu <mhiramat@redhat.com> | 2009-03-06 10:37:54 -0500 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-03-06 16:49:01 +0100 |
| commit | 78ff7fae04554b49d29226ed12536268c2500d1f (patch) | |
| tree | 377980e0543a7c9d0f6567498a186284ae85e432 | |
| parent | 3945dab45aa8c89014893bfa8eb1e1661a409cef (diff) | |
| download | blackbird-op-linux-78ff7fae04554b49d29226ed12536268c2500d1f.tar.gz blackbird-op-linux-78ff7fae04554b49d29226ed12536268c2500d1f.zip | |
x86: implement atomic text_poke() via fixmap
Use fixmaps instead of vmap/vunmap in text_poke() for avoiding
page allocation and delayed unmapping.
At the result of above change, text_poke() becomes atomic and can be called
from stop_machine() etc.
Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
LKML-Reference: <49B14352.2040705@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
| -rw-r--r-- | arch/x86/include/asm/fixmap.h | 2 | ||||
| -rw-r--r-- | arch/x86/kernel/alternative.c | 24 |
2 files changed, 17 insertions, 9 deletions
diff --git a/arch/x86/include/asm/fixmap.h b/arch/x86/include/asm/fixmap.h index 63a79c77d220..81937a5dc77c 100644 --- a/arch/x86/include/asm/fixmap.h +++ b/arch/x86/include/asm/fixmap.h @@ -111,6 +111,8 @@ enum fixed_addresses { #ifdef CONFIG_PARAVIRT FIX_PARAVIRT_BOOTMAP, #endif + FIX_TEXT_POKE0, /* reserve 2 pages for text_poke() */ + FIX_TEXT_POKE1, __end_of_permanent_fixed_addresses, #ifdef CONFIG_PROVIDE_OHCI1394_DMA_INIT FIX_OHCI1394_BASE, diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c index 092a7b8be68d..2d903b760ddb 100644 --- a/arch/x86/kernel/alternative.c +++ b/arch/x86/kernel/alternative.c @@ -13,7 +13,9 @@ #include <asm/nmi.h> #include <asm/vsyscall.h> #include <asm/cacheflush.h> +#include <asm/tlbflush.h> #include <asm/io.h> +#include <asm/fixmap.h> #define MAX_PATCH_LEN (255-1) @@ -505,15 +507,16 @@ void *text_poke_early(void *addr, const void *opcode, size_t len) * It means the size must be writable atomically and the address must be aligned * in a way that permits an atomic write. It also makes sure we fit on a single * page. + * + * Note: Must be called under text_mutex. */ void *__kprobes text_poke(void *addr, const void *opcode, size_t len) { + unsigned long flags; char *vaddr; - int nr_pages = 2; struct page *pages[2]; int i; - might_sleep(); if (!core_kernel_text((unsigned long)addr)) { pages[0] = vmalloc_to_page(addr); pages[1] = vmalloc_to_page(addr + PAGE_SIZE); @@ -523,14 +526,17 @@ void *__kprobes text_poke(void *addr, const void *opcode, size_t len) pages[1] = virt_to_page(addr + PAGE_SIZE); } BUG_ON(!pages[0]); - if (!pages[1]) - nr_pages = 1; - vaddr = vmap(pages, nr_pages, VM_MAP, PAGE_KERNEL); - BUG_ON(!vaddr); - local_irq_disable(); + set_fixmap(FIX_TEXT_POKE0, page_to_phys(pages[0])); + if (pages[1]) + set_fixmap(FIX_TEXT_POKE1, page_to_phys(pages[1])); + vaddr = (char *)fix_to_virt(FIX_TEXT_POKE0); + local_irq_save(flags); memcpy(&vaddr[(unsigned long)addr & ~PAGE_MASK], opcode, len); - local_irq_enable(); - vunmap(vaddr); + local_irq_restore(flags); + clear_fixmap(FIX_TEXT_POKE0); + if (pages[1]) + clear_fixmap(FIX_TEXT_POKE1); + local_flush_tlb(); sync_core(); /* Could also do a CLFLUSH here to speed up CPU recovery; but that causes hangs on some VIA CPUs. */ |
