From cb3ac45214c03852430979a43180371a44b74596 Mon Sep 17 00:00:00 2001 From: Christophe Leroy Date: Tue, 22 Mar 2022 16:40:18 +0100 Subject: powerpc/code-patching: Don't call is_vmalloc_or_module_addr() without CONFIG_MODULES If CONFIG_MODULES is not set, there is no point in checking whether text is in module area. This reduced the time needed to activate/deactivate ftrace by more than 10% on an 8xx. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/f3c701cce00a38620788c0fc43ff0b611a268c54.1647962456.git.christophe.leroy@csgroup.eu --- arch/powerpc/lib/code-patching.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (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 00c68e7fb11e..f970f189875b 100644 --- a/arch/powerpc/lib/code-patching.c +++ b/arch/powerpc/lib/code-patching.c @@ -97,7 +97,7 @@ static int map_patch_area(void *addr, unsigned long text_poke_addr) { unsigned long pfn; - if (is_vmalloc_or_module_addr(addr)) + if (IS_ENABLED(CONFIG_MODULES) && is_vmalloc_or_module_addr(addr)) pfn = vmalloc_to_pfn(addr); else pfn = __pa_symbol(addr) >> PAGE_SHIFT; -- cgit v1.2.3 From b033767848c4115e486b1a51946de3bee2ac0fa6 Mon Sep 17 00:00:00 2001 From: Christophe Leroy Date: Tue, 22 Mar 2022 16:40:20 +0100 Subject: powerpc/code-patching: Use jump_label for testing freed initmem Once init is done, initmem is freed forever so no need to test system_state at every call to patch_instruction(). Use jump_label. This reduces by 2% the time needed to activate ftrace on an 8xx. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/0aee964721cab7316cffde21a2ca223cee14d373.1647962456.git.christophe.leroy@csgroup.eu --- arch/powerpc/include/asm/code-patching.h | 2 ++ arch/powerpc/lib/code-patching.c | 5 ++++- arch/powerpc/mm/mem.c | 2 ++ 3 files changed, 8 insertions(+), 1 deletion(-) (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 409483b2d0ce..bccc3a538b9f 100644 --- a/arch/powerpc/include/asm/code-patching.h +++ b/arch/powerpc/include/asm/code-patching.h @@ -22,6 +22,8 @@ #define BRANCH_SET_LINK 0x1 #define BRANCH_ABSOLUTE 0x2 +DECLARE_STATIC_KEY_FALSE(init_mem_is_free); + bool is_offset_in_branch_range(long offset); bool is_offset_in_cond_branch_range(long offset); int create_branch(ppc_inst_t *instr, const u32 *addr, diff --git a/arch/powerpc/lib/code-patching.c b/arch/powerpc/lib/code-patching.c index f970f189875b..1ecd166091c9 100644 --- a/arch/powerpc/lib/code-patching.c +++ b/arch/powerpc/lib/code-patching.c @@ -8,6 +8,7 @@ #include #include #include +#include #include #include @@ -188,10 +189,12 @@ static int do_patch_instruction(u32 *addr, ppc_inst_t instr) #endif /* CONFIG_STRICT_KERNEL_RWX */ +__ro_after_init DEFINE_STATIC_KEY_FALSE(init_mem_is_free); + int patch_instruction(u32 *addr, ppc_inst_t instr) { /* Make sure we aren't patching a freed init section */ - if (system_state >= SYSTEM_FREEING_INITMEM && init_section_contains(addr, 4)) + if (static_branch_likely(&init_mem_is_free) && init_section_contains(addr, 4)) return 0; return do_patch_instruction(addr, instr); diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c index 4d221d033804..177fae5ea0d1 100644 --- a/arch/powerpc/mm/mem.c +++ b/arch/powerpc/mm/mem.c @@ -22,6 +22,7 @@ #include #include #include +#include #include @@ -311,6 +312,7 @@ void free_initmem(void) { ppc_md.progress = ppc_printk_progress; mark_initmem_nx(); + static_branch_enable(&init_mem_is_free); free_initmem_default(POISON_FREE_INITMEM); } -- cgit v1.2.3 From 1751289268ef959db68b0b6f798d904d6403309a Mon Sep 17 00:00:00 2001 From: Christophe Leroy Date: Tue, 22 Mar 2022 16:40:21 +0100 Subject: powerpc/code-patching: Use jump_label to check if poking_init() is done It's only during early startup that poking_init() is not done yet, for instance when calling ftrace_init(). Once poking_init() has been called there must be a poking area, no need to check it everytime patch_instruction() is called. ftrace activation time is reduced by 7% with the change on an 8xx. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/8d6088aca7b63247377b6d9e4897d08d935fbe93.1647962456.git.christophe.leroy@csgroup.eu --- arch/powerpc/lib/code-patching.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (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 1ecd166091c9..be670e1abafa 100644 --- a/arch/powerpc/lib/code-patching.c +++ b/arch/powerpc/lib/code-patching.c @@ -79,6 +79,8 @@ static int text_area_cpu_down(unsigned int cpu) return 0; } +static __ro_after_init DEFINE_STATIC_KEY_FALSE(poking_init_done); + /* * Although BUG_ON() is rude, in this case it should only happen if ENOMEM, and * we judge it as being preferable to a kernel that will crash later when @@ -89,6 +91,7 @@ void __init poking_init(void) BUG_ON(!cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "powerpc/text_poke:online", text_area_cpu_up, text_area_cpu_down)); + static_branch_enable(&poking_init_done); } /* @@ -171,7 +174,7 @@ static int do_patch_instruction(u32 *addr, ppc_inst_t 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(text_poke_area)) + if (!static_branch_likely(&poking_init_done)) return raw_patch_instruction(addr, instr); local_irq_save(flags); -- cgit v1.2.3 From 1acbf27e8a5843911d122ad0008e79ec5f7b6382 Mon Sep 17 00:00:00 2001 From: Christophe Leroy Date: Mon, 9 May 2022 07:36:01 +0200 Subject: powerpc/code-patching: Inline is_offset_in_{cond}_branch_range() Test in is_offset_in_branch_range() and is_offset_in_cond_branch_range() are simple tests that are worth inlining. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/a05be0ccb7373e6a9789a1988fcd0c810f5f9269.1652074503.git.christophe.leroy@csgroup.eu --- arch/powerpc/include/asm/code-patching.h | 29 +++++++++++++++++++++++++++-- arch/powerpc/lib/code-patching.c | 27 --------------------------- 2 files changed, 27 insertions(+), 29 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 bccc3a538b9f..378b70545a32 100644 --- a/arch/powerpc/include/asm/code-patching.h +++ b/arch/powerpc/include/asm/code-patching.h @@ -24,8 +24,33 @@ DECLARE_STATIC_KEY_FALSE(init_mem_is_free); -bool is_offset_in_branch_range(long offset); -bool is_offset_in_cond_branch_range(long offset); +/* + * Powerpc branch instruction is : + * + * 0 6 30 31 + * +---------+----------------+---+---+ + * | opcode | LI |AA |LK | + * +---------+----------------+---+---+ + * Where AA = 0 and LK = 0 + * + * LI is a signed 24 bits integer. The real branch offset is computed + * by: imm32 = SignExtend(LI:'0b00', 32); + * + * So the maximum forward branch should be: + * (0x007fffff << 2) = 0x01fffffc = 0x1fffffc + * The maximum backward branch should be: + * (0xff800000 << 2) = 0xfe000000 = -0x2000000 + */ +static inline bool is_offset_in_branch_range(long offset) +{ + return (offset >= -0x2000000 && offset <= 0x1fffffc && !(offset & 0x3)); +} + +static inline bool is_offset_in_cond_branch_range(long offset) +{ + return offset >= -0x8000 && offset <= 0x7fff && !(offset & 0x3); +} + int create_branch(ppc_inst_t *instr, const u32 *addr, unsigned long target, int flags); int create_cond_branch(ppc_inst_t *instr, const u32 *addr, diff --git a/arch/powerpc/lib/code-patching.c b/arch/powerpc/lib/code-patching.c index be670e1abafa..13a5a386d35b 100644 --- a/arch/powerpc/lib/code-patching.c +++ b/arch/powerpc/lib/code-patching.c @@ -214,33 +214,6 @@ int patch_branch(u32 *addr, unsigned long target, int flags) return patch_instruction(addr, instr); } -bool is_offset_in_branch_range(long offset) -{ - /* - * Powerpc branch instruction is : - * - * 0 6 30 31 - * +---------+----------------+---+---+ - * | opcode | LI |AA |LK | - * +---------+----------------+---+---+ - * Where AA = 0 and LK = 0 - * - * LI is a signed 24 bits integer. The real branch offset is computed - * by: imm32 = SignExtend(LI:'0b00', 32); - * - * So the maximum forward branch should be: - * (0x007fffff << 2) = 0x01fffffc = 0x1fffffc - * The maximum backward branch should be: - * (0xff800000 << 2) = 0xfe000000 = -0x2000000 - */ - return (offset >= -0x2000000 && offset <= 0x1fffffc && !(offset & 0x3)); -} - -bool is_offset_in_cond_branch_range(long offset) -{ - return offset >= -0x8000 && offset <= 0x7fff && !(offset & 0x3); -} - /* * Helper to check if a given instruction is a conditional branch * Derived from the conditional checks in analyse_instr() -- cgit v1.2.3 From d2f47dabf1252520a88d257133e6bdec474fd935 Mon Sep 17 00:00:00 2001 From: Christophe Leroy Date: Mon, 9 May 2022 07:36:03 +0200 Subject: powerpc/code-patching: Inline create_branch() create_branch() is a good candidate for inlining because: - Flags can be folded in. - Range tests are likely to be already done. Hence reducing the create_branch() to only a set of instructions. So inline it. It improves ftrace activation by 10%. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/69851cc9a7bf8f03d025e6d29e165f2d0bd3bb6e.1652074503.git.christophe.leroy@csgroup.eu --- arch/powerpc/include/asm/code-patching.h | 22 ++++++++++++++++++++-- arch/powerpc/lib/code-patching.c | 20 -------------------- 2 files changed, 20 insertions(+), 22 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 378b70545a32..947d4ae062f5 100644 --- a/arch/powerpc/include/asm/code-patching.h +++ b/arch/powerpc/include/asm/code-patching.h @@ -51,8 +51,26 @@ static inline bool is_offset_in_cond_branch_range(long offset) return offset >= -0x8000 && offset <= 0x7fff && !(offset & 0x3); } -int create_branch(ppc_inst_t *instr, const u32 *addr, - unsigned long target, int flags); +static inline int create_branch(ppc_inst_t *instr, const u32 *addr, + unsigned long target, int flags) +{ + long offset; + + *instr = ppc_inst(0); + offset = target; + if (! (flags & BRANCH_ABSOLUTE)) + offset = offset - (unsigned long)addr; + + /* Check we can represent the target in the instruction format */ + if (!is_offset_in_branch_range(offset)) + return 1; + + /* Mask out the flags and target, so they don't step on each other. */ + *instr = ppc_inst(0x48000000 | (flags & 0x3) | (offset & 0x03FFFFFC)); + + return 0; +} + int create_cond_branch(ppc_inst_t *instr, const u32 *addr, unsigned long target, int flags); int patch_branch(u32 *addr, unsigned long target, int flags); diff --git a/arch/powerpc/lib/code-patching.c b/arch/powerpc/lib/code-patching.c index 13a5a386d35b..46ffce27135e 100644 --- a/arch/powerpc/lib/code-patching.c +++ b/arch/powerpc/lib/code-patching.c @@ -236,26 +236,6 @@ bool is_conditional_branch(ppc_inst_t instr) } NOKPROBE_SYMBOL(is_conditional_branch); -int create_branch(ppc_inst_t *instr, const u32 *addr, - unsigned long target, int flags) -{ - long offset; - - *instr = ppc_inst(0); - offset = target; - if (! (flags & BRANCH_ABSOLUTE)) - offset = offset - (unsigned long)addr; - - /* Check we can represent the target in the instruction format */ - if (!is_offset_in_branch_range(offset)) - return 1; - - /* Mask out the flags and target, so they don't step on each other. */ - *instr = ppc_inst(0x48000000 | (flags & 0x3) | (offset & 0x03FFFFFC)); - - return 0; -} - int create_cond_branch(ppc_inst_t *instr, const u32 *addr, unsigned long target, int flags) { -- cgit v1.2.3 From bbffdd2fc743bdc529f9a8264bdb5d3491f58c95 Mon Sep 17 00:00:00 2001 From: Christophe Leroy Date: Mon, 9 May 2022 07:36:05 +0200 Subject: powerpc/ftrace: Use patch_instruction() return directly Instead of returning -EPERM when patch_instruction() fails, just return what patch_instruction returns. That simplifies ftrace_modify_code(): 0: 94 21 ff c0 stwu r1,-64(r1) 4: 93 e1 00 3c stw r31,60(r1) 8: 7c 7f 1b 79 mr. r31,r3 c: 40 80 00 30 bge 3c 10: 93 c1 00 38 stw r30,56(r1) 14: 7c 9e 23 78 mr r30,r4 18: 7c a4 2b 78 mr r4,r5 1c: 80 bf 00 00 lwz r5,0(r31) 20: 7c 1e 28 40 cmplw r30,r5 24: 40 82 00 34 bne 58 28: 83 c1 00 38 lwz r30,56(r1) 2c: 7f e3 fb 78 mr r3,r31 30: 83 e1 00 3c lwz r31,60(r1) 34: 38 21 00 40 addi r1,r1,64 38: 48 00 00 00 b 38 38: R_PPC_REL24 patch_instruction Before: 0: 94 21 ff c0 stwu r1,-64(r1) 4: 93 e1 00 3c stw r31,60(r1) 8: 7c 7f 1b 79 mr. r31,r3 c: 40 80 00 4c bge 58 10: 93 c1 00 38 stw r30,56(r1) 14: 7c 9e 23 78 mr r30,r4 18: 7c a4 2b 78 mr r4,r5 1c: 80 bf 00 00 lwz r5,0(r31) 20: 7c 08 02 a6 mflr r0 24: 90 01 00 44 stw r0,68(r1) 28: 7c 1e 28 40 cmplw r30,r5 2c: 40 82 00 48 bne 74 30: 7f e3 fb 78 mr r3,r31 34: 48 00 00 01 bl 34 34: R_PPC_REL24 patch_instruction 38: 80 01 00 44 lwz r0,68(r1) 3c: 20 63 00 00 subfic r3,r3,0 40: 83 c1 00 38 lwz r30,56(r1) 44: 7c 63 19 10 subfe r3,r3,r3 48: 7c 08 03 a6 mtlr r0 4c: 83 e1 00 3c lwz r31,60(r1) 50: 38 21 00 40 addi r1,r1,64 54: 4e 80 00 20 blr It improves ftrace activation/deactivation duration by about 3%. Modify patch_instruction() return on failure to -EPERM in order to match with ftrace expectations. Other users of patch_instruction() do not care about the exact error value returned. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/49a8597230713e2633e7d9d7b56140787c4a7e20.1652074503.git.christophe.leroy@csgroup.eu --- arch/powerpc/kernel/trace/ftrace.c | 5 +---- arch/powerpc/lib/code-patching.c | 2 +- 2 files changed, 2 insertions(+), 5 deletions(-) (limited to 'arch/powerpc/lib/code-patching.c') diff --git a/arch/powerpc/kernel/trace/ftrace.c b/arch/powerpc/kernel/trace/ftrace.c index 98e82fa4980f..1b05d33f96c6 100644 --- a/arch/powerpc/kernel/trace/ftrace.c +++ b/arch/powerpc/kernel/trace/ftrace.c @@ -78,10 +78,7 @@ ftrace_modify_code(unsigned long ip, ppc_inst_t old, ppc_inst_t new) } /* replace the text with the new text */ - if (patch_instruction((u32 *)ip, new)) - return -EPERM; - - return 0; + return patch_instruction((u32 *)ip, new); } /* diff --git a/arch/powerpc/lib/code-patching.c b/arch/powerpc/lib/code-patching.c index 46ffce27135e..6edf0697a526 100644 --- a/arch/powerpc/lib/code-patching.c +++ b/arch/powerpc/lib/code-patching.c @@ -33,7 +33,7 @@ static int __patch_instruction(u32 *exec_addr, ppc_inst_t instr, u32 *patch_addr return 0; failed: - return -EFAULT; + return -EPERM; } int raw_patch_instruction(u32 *addr, ppc_inst_t instr) -- cgit v1.2.3