From 4e87ace902cf0d401376cac89bb6a5239e57fe9f Mon Sep 17 00:00:00 2001 From: Sven Schnelle Date: Wed, 5 Jun 2019 22:32:17 +0200 Subject: parisc: add support for patching multiple words add patch_text_multiple() which allows to patch multiple text words in memory. This can be used to copy functions. Signed-off-by: Sven Schnelle Signed-off-by: Helge Deller --- arch/parisc/kernel/patch.c | 75 ++++++++++++++++++++++++++++++++++++---------- 1 file changed, 59 insertions(+), 16 deletions(-) (limited to 'arch/parisc/kernel/patch.c') diff --git a/arch/parisc/kernel/patch.c b/arch/parisc/kernel/patch.c index cdcd981278b3..70e9997a3f80 100644 --- a/arch/parisc/kernel/patch.c +++ b/arch/parisc/kernel/patch.c @@ -17,15 +17,18 @@ struct patch { void *addr; - unsigned int insn; + u32 *insn; + unsigned int len; }; -static void __kprobes *patch_map(void *addr, int fixmap) -{ +static DEFINE_RAW_SPINLOCK(patch_lock); + +static void __kprobes *patch_map(void *addr, int fixmap, int *need_unmap) unsigned long uintaddr = (uintptr_t) addr; bool module = !core_kernel_text(uintaddr); struct page *page; + *need_unmap = 0; if (module && IS_ENABLED(CONFIG_STRICT_MODULE_RWX)) page = vmalloc_to_page(addr); else if (!module && IS_ENABLED(CONFIG_STRICT_KERNEL_RWX)) @@ -33,6 +36,7 @@ static void __kprobes *patch_map(void *addr, int fixmap) else return addr; + *need_unmap = 1; set_fixmap(fixmap, page_to_phys(page)); return (void *) (__fix_to_virt(fixmap) + (uintaddr & ~PAGE_MASK)); @@ -43,34 +47,73 @@ static void __kprobes patch_unmap(int fixmap) clear_fixmap(fixmap); } -void __kprobes __patch_text(void *addr, unsigned int insn) +void __kprobes __patch_text_multiple(void *addr, u32 *insn, unsigned int len) +{ + unsigned long start = (unsigned long)addr; + unsigned long end = (unsigned long)addr + len; + u32 *p, *fixmap; + int mapped; + + /* Make sure we don't have any aliases in cache */ + flush_kernel_vmap_range(addr, len); + flush_icache_range(start, end); + + p = fixmap = patch_map(addr, FIX_TEXT_POKE0, &mapped); + + while (len >= 4) { + *p++ = *insn++; + addr += sizeof(u32); + len -= sizeof(u32); + if (len && offset_in_page(addr) == 0) { + /* + * We're crossing a page boundary, so + * need to remap + */ + flush_kernel_vmap_range((void *)fixmap, + (p-fixmap) * sizeof(*p)); + if (mapped) + patch_unmap(FIX_TEXT_POKE0); + p = fixmap = patch_map(addr, FIX_TEXT_POKE0, &mapped); + } + } + + flush_kernel_vmap_range((void *)fixmap, (p-fixmap) * sizeof(*p)); + if (mapped) + patch_unmap(FIX_TEXT_POKE0); + flush_icache_range(start, end); +} + +void __kprobes __patch_text(void *addr, u32 insn) { - void *waddr = addr; - int size; - - waddr = patch_map(addr, FIX_TEXT_POKE0); - *(u32 *)waddr = insn; - size = sizeof(u32); - flush_kernel_vmap_range(waddr, size); - patch_unmap(FIX_TEXT_POKE0); - flush_icache_range((uintptr_t)(addr), - (uintptr_t)(addr) + size); + __patch_text_multiple(addr, &insn, sizeof(insn)); } static int __kprobes patch_text_stop_machine(void *data) { struct patch *patch = data; - __patch_text(patch->addr, patch->insn); - + __patch_text_multiple(patch->addr, patch->insn, patch->len); return 0; } void __kprobes patch_text(void *addr, unsigned int insn) { + struct patch patch = { + .addr = addr, + .insn = &insn, + .len = sizeof(insn), + }; + + stop_machine_cpuslocked(patch_text_stop_machine, &patch, NULL); +} + +void __kprobes patch_text_multiple(void *addr, u32 *insn, unsigned int len) +{ + struct patch patch = { .addr = addr, .insn = insn, + .len = len }; stop_machine_cpuslocked(patch_text_stop_machine, &patch, NULL); -- cgit v1.2.3 From 7e923369b1ec92af5f048d2146b44f9132abe1ad Mon Sep 17 00:00:00 2001 From: Sven Schnelle Date: Wed, 5 Jun 2019 22:32:18 +0200 Subject: parisc: add spinlock to patch function If multiple CPUs are patching code we need the spinlock to protect against parallel fixmap maps/unmap calls. Signed-off-by: Sven Schnelle Signed-off-by: Helge Deller --- arch/parisc/kernel/patch.c | 25 +++++++++++++++++++------ 1 file changed, 19 insertions(+), 6 deletions(-) (limited to 'arch/parisc/kernel/patch.c') diff --git a/arch/parisc/kernel/patch.c b/arch/parisc/kernel/patch.c index 70e9997a3f80..80a0ab372802 100644 --- a/arch/parisc/kernel/patch.c +++ b/arch/parisc/kernel/patch.c @@ -23,7 +23,9 @@ struct patch { static DEFINE_RAW_SPINLOCK(patch_lock); -static void __kprobes *patch_map(void *addr, int fixmap, int *need_unmap) +static void __kprobes *patch_map(void *addr, int fixmap, unsigned long *flags, + int *need_unmap) +{ unsigned long uintaddr = (uintptr_t) addr; bool module = !core_kernel_text(uintaddr); struct page *page; @@ -38,19 +40,29 @@ static void __kprobes *patch_map(void *addr, int fixmap, int *need_unmap) *need_unmap = 1; set_fixmap(fixmap, page_to_phys(page)); + if (flags) + raw_spin_lock_irqsave(&patch_lock, *flags); + else + __acquire(&patch_lock); return (void *) (__fix_to_virt(fixmap) + (uintaddr & ~PAGE_MASK)); } -static void __kprobes patch_unmap(int fixmap) +static void __kprobes patch_unmap(int fixmap, unsigned long *flags) { clear_fixmap(fixmap); + + if (flags) + raw_spin_unlock_irqrestore(&patch_lock, *flags); + else + __release(&patch_lock); } void __kprobes __patch_text_multiple(void *addr, u32 *insn, unsigned int len) { unsigned long start = (unsigned long)addr; unsigned long end = (unsigned long)addr + len; + unsigned long flags; u32 *p, *fixmap; int mapped; @@ -58,7 +70,7 @@ void __kprobes __patch_text_multiple(void *addr, u32 *insn, unsigned int len) flush_kernel_vmap_range(addr, len); flush_icache_range(start, end); - p = fixmap = patch_map(addr, FIX_TEXT_POKE0, &mapped); + p = fixmap = patch_map(addr, FIX_TEXT_POKE0, &flags, &mapped); while (len >= 4) { *p++ = *insn++; @@ -72,14 +84,15 @@ void __kprobes __patch_text_multiple(void *addr, u32 *insn, unsigned int len) flush_kernel_vmap_range((void *)fixmap, (p-fixmap) * sizeof(*p)); if (mapped) - patch_unmap(FIX_TEXT_POKE0); - p = fixmap = patch_map(addr, FIX_TEXT_POKE0, &mapped); + patch_unmap(FIX_TEXT_POKE0, &flags); + p = fixmap = patch_map(addr, FIX_TEXT_POKE0, &flags, + &mapped); } } flush_kernel_vmap_range((void *)fixmap, (p-fixmap) * sizeof(*p)); if (mapped) - patch_unmap(FIX_TEXT_POKE0); + patch_unmap(FIX_TEXT_POKE0, &flags); flush_icache_range(start, end); } -- cgit v1.2.3