From b9eab08d012fa093947b230f9a87257c27fb829b Mon Sep 17 00:00:00 2001 From: Josh Poimboeuf Date: Thu, 16 Nov 2017 11:45:37 -0600 Subject: powerpc/modules: Don't try to restore r2 after a sibling call When attempting to load a livepatch module, I got the following error: module_64: patch_module: Expect noop after relocate, got 3c820000 The error was triggered by the following code in unregister_netdevice_queue(): 14c: 00 00 00 48 b 14c 14c: R_PPC64_REL24 net_set_todo 150: 00 00 82 3c addis r4,r2,0 GCC didn't insert a nop after the branch to net_set_todo() because it's a sibling call, so it never returns. The nop isn't needed after the branch in that case. Signed-off-by: Josh Poimboeuf Acked-by: Naveen N. Rao Reviewed-and-tested-by: Kamalesh Babulal Signed-off-by: Michael Ellerman --- arch/powerpc/lib/code-patching.c | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'arch/powerpc/lib/code-patching.c') diff --git a/arch/powerpc/lib/code-patching.c b/arch/powerpc/lib/code-patching.c index d469224c4ada..096d4e4d31e6 100644 --- a/arch/powerpc/lib/code-patching.c +++ b/arch/powerpc/lib/code-patching.c @@ -302,6 +302,11 @@ int instr_is_relative_branch(unsigned int instr) return instr_is_branch_iform(instr) || instr_is_branch_bform(instr); } +int instr_is_relative_link_branch(unsigned int instr) +{ + return instr_is_relative_branch(instr) && (instr & BRANCH_SET_LINK); +} + static unsigned long branch_iform_target(const unsigned int *instr) { signed long imm; -- cgit v1.2.3 From 8cf4c05712f04a405f0dacebcca8f042b391694a Mon Sep 17 00:00:00 2001 From: Christophe Leroy Date: Fri, 24 Nov 2017 08:31:07 +0100 Subject: powerpc/lib/code-patching: refactor patch_instruction() patch_instruction() uses almost the same sequence as __patch_instruction() This patch refactor it so that patch_instruction() uses __patch_instruction() instead of duplicating code. Signed-off-by: Christophe Leroy Acked-by: Balbir Singh Signed-off-by: Michael Ellerman --- arch/powerpc/lib/code-patching.c | 30 +++++++++++++++--------------- 1 file changed, 15 insertions(+), 15 deletions(-) (limited to 'arch/powerpc/lib/code-patching.c') diff --git a/arch/powerpc/lib/code-patching.c b/arch/powerpc/lib/code-patching.c index 096d4e4d31e6..e1c58937281f 100644 --- a/arch/powerpc/lib/code-patching.c +++ b/arch/powerpc/lib/code-patching.c @@ -23,19 +23,26 @@ #include #include -static int __patch_instruction(unsigned int *addr, unsigned int instr) +static int __patch_instruction(unsigned int *exec_addr, unsigned int instr, + unsigned int *patch_addr) { int err; - __put_user_size(instr, addr, 4, err); + __put_user_size(instr, patch_addr, 4, err); if (err) return err; - asm ("dcbst 0, %0; sync; icbi 0,%0; sync; isync" :: "r" (addr)); + asm ("dcbst 0, %0; sync; icbi 0,%1; sync; isync" :: "r" (patch_addr), + "r" (exec_addr)); return 0; } +static int raw_patch_instruction(unsigned int *addr, unsigned int instr) +{ + return __patch_instruction(addr, instr, addr); +} + #ifdef CONFIG_STRICT_KERNEL_RWX static DEFINE_PER_CPU(struct vm_struct *, text_poke_area); @@ -138,7 +145,7 @@ static inline int unmap_patch_area(unsigned long addr) int patch_instruction(unsigned int *addr, unsigned int instr) { int err; - unsigned int *dest = NULL; + unsigned int *patch_addr = NULL; unsigned long flags; unsigned long text_poke_addr; unsigned long kaddr = (unsigned long)addr; @@ -149,7 +156,7 @@ int patch_instruction(unsigned int *addr, unsigned int instr) * to allow patching. We just do the plain old patching */ if (!this_cpu_read(*PTRRELOC(&text_poke_area))) - return __patch_instruction(addr, instr); + return raw_patch_instruction(addr, instr); local_irq_save(flags); @@ -159,17 +166,10 @@ int patch_instruction(unsigned int *addr, unsigned int instr) goto out; } - dest = (unsigned int *)(text_poke_addr) + + patch_addr = (unsigned int *)(text_poke_addr) + ((kaddr & ~PAGE_MASK) / sizeof(unsigned int)); - /* - * We use __put_user_size so that we can handle faults while - * writing to dest and return err to handle faults gracefully - */ - __put_user_size(instr, dest, 4, err); - if (!err) - asm ("dcbst 0, %0; sync; icbi 0,%0; icbi 0,%1; sync; isync" - ::"r" (dest), "r"(addr)); + __patch_instruction(addr, instr, patch_addr); err = unmap_patch_area(text_poke_addr); if (err) @@ -184,7 +184,7 @@ out: int patch_instruction(unsigned int *addr, unsigned int instr) { - return __patch_instruction(addr, instr); + return raw_patch_instruction(addr, instr); } #endif /* CONFIG_STRICT_KERNEL_RWX */ -- cgit v1.2.3 From 8183d99f4a22c2abbc543847a588df3666ef0c0c Mon Sep 17 00:00:00 2001 From: Christophe Leroy Date: Fri, 24 Nov 2017 08:31:09 +0100 Subject: powerpc/lib/feature-fixups: use raw_patch_instruction() feature fixups need to use patch_instruction() early in the boot, even before the code is relocated to its final address, requiring patch_instruction() to use PTRRELOC() in order to address data. But feature fixups applies on code before it is set to read only, even for modules. Therefore, feature fixups can use raw_patch_instruction() instead. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman --- arch/powerpc/include/asm/code-patching.h | 1 + arch/powerpc/lib/code-patching.c | 4 ++-- arch/powerpc/lib/feature-fixups.c | 8 ++++---- 3 files changed, 7 insertions(+), 6 deletions(-) (limited to 'arch/powerpc/lib/code-patching.c') diff --git a/arch/powerpc/include/asm/code-patching.h b/arch/powerpc/include/asm/code-patching.h index 2c895e8d07f7..812535f40124 100644 --- a/arch/powerpc/include/asm/code-patching.h +++ b/arch/powerpc/include/asm/code-patching.h @@ -31,6 +31,7 @@ unsigned int create_cond_branch(const unsigned int *addr, unsigned long target, int flags); int patch_branch(unsigned int *addr, unsigned long target, int flags); int patch_instruction(unsigned int *addr, unsigned int instr); +int raw_patch_instruction(unsigned int *addr, unsigned int instr); int instr_is_relative_branch(unsigned int instr); int instr_is_relative_link_branch(unsigned int instr); diff --git a/arch/powerpc/lib/code-patching.c b/arch/powerpc/lib/code-patching.c index e1c58937281f..e0d881ab304e 100644 --- a/arch/powerpc/lib/code-patching.c +++ b/arch/powerpc/lib/code-patching.c @@ -38,7 +38,7 @@ static int __patch_instruction(unsigned int *exec_addr, unsigned int instr, return 0; } -static int raw_patch_instruction(unsigned int *addr, unsigned int instr) +int raw_patch_instruction(unsigned int *addr, unsigned int instr) { return __patch_instruction(addr, instr, addr); } @@ -155,7 +155,7 @@ int patch_instruction(unsigned int *addr, unsigned int instr) * when text_poke_area is not ready, but we still need * to allow patching. We just do the plain old patching */ - if (!this_cpu_read(*PTRRELOC(&text_poke_area))) + if (!this_cpu_read(text_poke_area)) return raw_patch_instruction(addr, instr); local_irq_save(flags); diff --git a/arch/powerpc/lib/feature-fixups.c b/arch/powerpc/lib/feature-fixups.c index 41cf5ae273cf..0872d60ede10 100644 --- a/arch/powerpc/lib/feature-fixups.c +++ b/arch/powerpc/lib/feature-fixups.c @@ -62,7 +62,7 @@ static int patch_alt_instruction(unsigned int *src, unsigned int *dest, } } - patch_instruction(dest, instr); + raw_patch_instruction(dest, instr); return 0; } @@ -91,7 +91,7 @@ static int patch_feature_section(unsigned long value, struct fixup_entry *fcur) } for (; dest < end; dest++) - patch_instruction(dest, PPC_INST_NOP); + raw_patch_instruction(dest, PPC_INST_NOP); return 0; } @@ -129,7 +129,7 @@ void do_lwsync_fixups(unsigned long value, void *fixup_start, void *fixup_end) for (; start < end; start++) { dest = (void *)start + *start; - patch_instruction(dest, PPC_INST_LWSYNC); + raw_patch_instruction(dest, PPC_INST_LWSYNC); } } @@ -147,7 +147,7 @@ static void do_final_fixups(void) length = (__end_interrupts - _stext) / sizeof(int); while (length--) { - patch_instruction(dest, *src); + raw_patch_instruction(dest, *src); src++; dest++; } -- cgit v1.2.3