From 74bb8c450459c35ea48806b582b634bbbb9ebb09 Mon Sep 17 00:00:00 2001 From: Petr Mladek Date: Mon, 17 Feb 2014 16:22:53 +0100 Subject: ftrace/x86: Fix order of warning messages when ftrace modifies code The colon at the end of the printk message suggests that it should get printed before the details printed by ftrace_bug(). When touching the line, let's use the preferred pr_warn() macro as suggested by checkpatch.pl. Link: http://lkml.kernel.org/r/1392650573-3390-5-git-send-email-pmladek@suse.cz Signed-off-by: Petr Mladek Signed-off-by: Steven Rostedt --- arch/x86/kernel/ftrace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/x86') diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c index 52819e816f87..3d837b00502b 100644 --- a/arch/x86/kernel/ftrace.c +++ b/arch/x86/kernel/ftrace.c @@ -621,8 +621,8 @@ void ftrace_replace_code(int enable) return; remove_breakpoints: + pr_warn("Failed on %s (%d):\n", report, count); ftrace_bug(ret, rec ? rec->ip : 0); - printk(KERN_WARNING "Failed on %s (%d):\n", report, count); for_ftrace_rec_iter(iter) { rec = ftrace_rec_iter_record(iter); /* -- cgit v1.2.2 From 94792ea07ce2cceef48803c4df3cb5efacb21c9a Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Tue, 6 May 2014 16:26:39 -0400 Subject: ftrace/x86: Get the current mcount addr for add_breakpoint() The add_breakpoint() code in the ftrace updating gets the address of what the call will become, but if the mcount address is changing from regs to non-regs ftrace_caller or vice versa, it will use what the record currently is. This is rather silly as the code should always use what is currently there regardless of if it's changing the regs function or just converting to a nop. Signed-off-by: Steven Rostedt --- arch/x86/kernel/ftrace.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) (limited to 'arch/x86') diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c index 3d837b00502b..4b3c195d4133 100644 --- a/arch/x86/kernel/ftrace.c +++ b/arch/x86/kernel/ftrace.c @@ -380,9 +380,9 @@ static int add_breakpoints(struct dyn_ftrace *rec, int enable) unsigned long ftrace_addr; int ret; - ret = ftrace_test_record(rec, enable); + ftrace_addr = get_ftrace_old_addr(rec); - ftrace_addr = get_ftrace_addr(rec); + ret = ftrace_test_record(rec, enable); switch (ret) { case FTRACE_UPDATE_IGNORE: @@ -394,8 +394,6 @@ static int add_breakpoints(struct dyn_ftrace *rec, int enable) case FTRACE_UPDATE_MODIFY_CALL_REGS: case FTRACE_UPDATE_MODIFY_CALL: - ftrace_addr = get_ftrace_old_addr(rec); - /* fall through */ case FTRACE_UPDATE_MAKE_NOP: /* converting a call to a nop */ return add_brk_on_call(rec, ftrace_addr); -- cgit v1.2.2 From 7413af1fb70e7efa6dbc7f27663e7a5126b3aa33 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Tue, 6 May 2014 21:34:14 -0400 Subject: ftrace: Make get_ftrace_addr() and get_ftrace_addr_old() global Move and rename get_ftrace_addr() and get_ftrace_addr_old() to ftrace_get_addr_new() and ftrace_get_addr_curr() respectively. This moves these two helper functions in the generic code out from the arch specific code, and renames them to have a better generic name. This will allow other archs to use them as well as makes it a bit easier to work on getting separate trampolines for different functions. ftrace_get_addr_new() returns the trampoline address that the mcount call address will be converted to. ftrace_get_addr_curr() returns the trampoline address of what the mcount call address currently jumps to. Signed-off-by: Steven Rostedt --- arch/x86/kernel/ftrace.c | 36 +++++------------------------------- 1 file changed, 5 insertions(+), 31 deletions(-) (limited to 'arch/x86') diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c index 4b3c195d4133..5ef43ce8492f 100644 --- a/arch/x86/kernel/ftrace.c +++ b/arch/x86/kernel/ftrace.c @@ -349,38 +349,12 @@ static int add_brk_on_nop(struct dyn_ftrace *rec) return add_break(rec->ip, old); } -/* - * If the record has the FTRACE_FL_REGS set, that means that it - * wants to convert to a callback that saves all regs. If FTRACE_FL_REGS - * is not not set, then it wants to convert to the normal callback. - */ -static unsigned long get_ftrace_addr(struct dyn_ftrace *rec) -{ - if (rec->flags & FTRACE_FL_REGS) - return (unsigned long)FTRACE_REGS_ADDR; - else - return (unsigned long)FTRACE_ADDR; -} - -/* - * The FTRACE_FL_REGS_EN is set when the record already points to - * a function that saves all the regs. Basically the '_EN' version - * represents the current state of the function. - */ -static unsigned long get_ftrace_old_addr(struct dyn_ftrace *rec) -{ - if (rec->flags & FTRACE_FL_REGS_EN) - return (unsigned long)FTRACE_REGS_ADDR; - else - return (unsigned long)FTRACE_ADDR; -} - static int add_breakpoints(struct dyn_ftrace *rec, int enable) { unsigned long ftrace_addr; int ret; - ftrace_addr = get_ftrace_old_addr(rec); + ftrace_addr = ftrace_get_addr_curr(rec); ret = ftrace_test_record(rec, enable); @@ -438,14 +412,14 @@ static int remove_breakpoint(struct dyn_ftrace *rec) * If not, don't touch the breakpoint, we make just create * a disaster. */ - ftrace_addr = get_ftrace_addr(rec); + ftrace_addr = ftrace_get_addr_new(rec); nop = ftrace_call_replace(ip, ftrace_addr); if (memcmp(&ins[1], &nop[1], MCOUNT_INSN_SIZE - 1) == 0) goto update; /* Check both ftrace_addr and ftrace_old_addr */ - ftrace_addr = get_ftrace_old_addr(rec); + ftrace_addr = ftrace_get_addr_curr(rec); nop = ftrace_call_replace(ip, ftrace_addr); if (memcmp(&ins[1], &nop[1], MCOUNT_INSN_SIZE - 1) != 0) @@ -489,7 +463,7 @@ static int add_update(struct dyn_ftrace *rec, int enable) ret = ftrace_test_record(rec, enable); - ftrace_addr = get_ftrace_addr(rec); + ftrace_addr = ftrace_get_addr_new(rec); switch (ret) { case FTRACE_UPDATE_IGNORE: @@ -536,7 +510,7 @@ static int finish_update(struct dyn_ftrace *rec, int enable) ret = ftrace_update_record(rec, enable); - ftrace_addr = get_ftrace_addr(rec); + ftrace_addr = ftrace_get_addr_new(rec); switch (ret) { case FTRACE_UPDATE_IGNORE: -- cgit v1.2.2 From f1b2f2bd5821c6ab7feed2e133343dd54b212ed9 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Wed, 7 May 2014 16:09:49 -0400 Subject: ftrace: Remove FTRACE_UPDATE_MODIFY_CALL_REGS flag As the decision to what needs to be done (converting a call to the ftrace_caller to ftrace_caller_regs or to convert from ftrace_caller_regs to ftrace_caller) can easily be determined from the rec->flags of FTRACE_FL_REGS and FTRACE_FL_REGS_EN, there's no need to have the ftrace_check_record() return either a UPDATE_MODIFY_CALL_REGS or a UPDATE_MODIFY_CALL. Just he latter is enough. This added flag causes more complexity than is required. Remove it. Signed-off-by: Steven Rostedt --- arch/x86/kernel/ftrace.c | 3 --- 1 file changed, 3 deletions(-) (limited to 'arch/x86') diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c index 5ef43ce8492f..89de3eaf8772 100644 --- a/arch/x86/kernel/ftrace.c +++ b/arch/x86/kernel/ftrace.c @@ -366,7 +366,6 @@ static int add_breakpoints(struct dyn_ftrace *rec, int enable) /* converting nop to call */ return add_brk_on_nop(rec); - case FTRACE_UPDATE_MODIFY_CALL_REGS: case FTRACE_UPDATE_MODIFY_CALL: case FTRACE_UPDATE_MAKE_NOP: /* converting a call to a nop */ @@ -469,7 +468,6 @@ static int add_update(struct dyn_ftrace *rec, int enable) case FTRACE_UPDATE_IGNORE: return 0; - case FTRACE_UPDATE_MODIFY_CALL_REGS: case FTRACE_UPDATE_MODIFY_CALL: case FTRACE_UPDATE_MAKE_CALL: /* converting nop to call */ @@ -516,7 +514,6 @@ static int finish_update(struct dyn_ftrace *rec, int enable) case FTRACE_UPDATE_IGNORE: return 0; - case FTRACE_UPDATE_MODIFY_CALL_REGS: case FTRACE_UPDATE_MODIFY_CALL: case FTRACE_UPDATE_MAKE_CALL: /* converting nop to call */ -- cgit v1.2.2 From e18eead3c3e0087b38b3ccec684808b6ee9ba7c3 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Thu, 8 May 2014 15:21:52 -0400 Subject: ftrace/x86: Move the mcount/fentry code out of entry_64.S As the mcount code gets more complex, it really does not belong in the entry.S file. By moving it into its own file "mcount.S" keeps things a bit cleaner. Link: http://lkml.kernel.org/p/20140508152152.2130e8cf@gandalf.local.home Acked-by: Thomas Gleixner Acked-by: Jiri Kosina Signed-off-by: Steven Rostedt --- arch/x86/kernel/Makefile | 1 + arch/x86/kernel/entry_64.S | 204 ----------------------------------------- arch/x86/kernel/mcount_64.S | 217 ++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 218 insertions(+), 204 deletions(-) create mode 100644 arch/x86/kernel/mcount_64.S (limited to 'arch/x86') diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile index f4d96000d33a..db7f41d74842 100644 --- a/arch/x86/kernel/Makefile +++ b/arch/x86/kernel/Makefile @@ -26,6 +26,7 @@ obj-$(CONFIG_IRQ_WORK) += irq_work.o obj-y += probe_roms.o obj-$(CONFIG_X86_32) += i386_ksyms_32.o obj-$(CONFIG_X86_64) += sys_x86_64.o x8664_ksyms_64.o +obj-$(CONFIG_X86_64) += mcount_64.o obj-y += syscall_$(BITS).o vsyscall_gtod.o obj-$(CONFIG_X86_64) += vsyscall_64.o obj-$(CONFIG_X86_64) += vsyscall_emu_64.o diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S index 1e96c3628bf2..3db806de57a0 100644 --- a/arch/x86/kernel/entry_64.S +++ b/arch/x86/kernel/entry_64.S @@ -53,7 +53,6 @@ #include #include #include -#include #include #include #include @@ -69,209 +68,6 @@ .code64 .section .entry.text, "ax" -#ifdef CONFIG_FUNCTION_TRACER - -#ifdef CC_USING_FENTRY -# define function_hook __fentry__ -#else -# define function_hook mcount -#endif - -#ifdef CONFIG_DYNAMIC_FTRACE - -ENTRY(function_hook) - retq -END(function_hook) - -/* skip is set if stack has been adjusted */ -.macro ftrace_caller_setup skip=0 - MCOUNT_SAVE_FRAME \skip - - /* Load the ftrace_ops into the 3rd parameter */ - movq function_trace_op(%rip), %rdx - - /* Load ip into the first parameter */ - movq RIP(%rsp), %rdi - subq $MCOUNT_INSN_SIZE, %rdi - /* Load the parent_ip into the second parameter */ -#ifdef CC_USING_FENTRY - movq SS+16(%rsp), %rsi -#else - movq 8(%rbp), %rsi -#endif -.endm - -ENTRY(ftrace_caller) - /* Check if tracing was disabled (quick check) */ - cmpl $0, function_trace_stop - jne ftrace_stub - - ftrace_caller_setup - /* regs go into 4th parameter (but make it NULL) */ - movq $0, %rcx - -GLOBAL(ftrace_call) - call ftrace_stub - - MCOUNT_RESTORE_FRAME -ftrace_return: - -#ifdef CONFIG_FUNCTION_GRAPH_TRACER -GLOBAL(ftrace_graph_call) - jmp ftrace_stub -#endif - -GLOBAL(ftrace_stub) - retq -END(ftrace_caller) - -ENTRY(ftrace_regs_caller) - /* Save the current flags before compare (in SS location)*/ - pushfq - - /* Check if tracing was disabled (quick check) */ - cmpl $0, function_trace_stop - jne ftrace_restore_flags - - /* skip=8 to skip flags saved in SS */ - ftrace_caller_setup 8 - - /* Save the rest of pt_regs */ - movq %r15, R15(%rsp) - movq %r14, R14(%rsp) - movq %r13, R13(%rsp) - movq %r12, R12(%rsp) - movq %r11, R11(%rsp) - movq %r10, R10(%rsp) - movq %rbp, RBP(%rsp) - movq %rbx, RBX(%rsp) - /* Copy saved flags */ - movq SS(%rsp), %rcx - movq %rcx, EFLAGS(%rsp) - /* Kernel segments */ - movq $__KERNEL_DS, %rcx - movq %rcx, SS(%rsp) - movq $__KERNEL_CS, %rcx - movq %rcx, CS(%rsp) - /* Stack - skipping return address */ - leaq SS+16(%rsp), %rcx - movq %rcx, RSP(%rsp) - - /* regs go into 4th parameter */ - leaq (%rsp), %rcx - -GLOBAL(ftrace_regs_call) - call ftrace_stub - - /* Copy flags back to SS, to restore them */ - movq EFLAGS(%rsp), %rax - movq %rax, SS(%rsp) - - /* Handlers can change the RIP */ - movq RIP(%rsp), %rax - movq %rax, SS+8(%rsp) - - /* restore the rest of pt_regs */ - movq R15(%rsp), %r15 - movq R14(%rsp), %r14 - movq R13(%rsp), %r13 - movq R12(%rsp), %r12 - movq R10(%rsp), %r10 - movq RBP(%rsp), %rbp - movq RBX(%rsp), %rbx - - /* skip=8 to skip flags saved in SS */ - MCOUNT_RESTORE_FRAME 8 - - /* Restore flags */ - popfq - - jmp ftrace_return -ftrace_restore_flags: - popfq - jmp ftrace_stub - -END(ftrace_regs_caller) - - -#else /* ! CONFIG_DYNAMIC_FTRACE */ - -ENTRY(function_hook) - cmpl $0, function_trace_stop - jne ftrace_stub - - cmpq $ftrace_stub, ftrace_trace_function - jnz trace - -#ifdef CONFIG_FUNCTION_GRAPH_TRACER - cmpq $ftrace_stub, ftrace_graph_return - jnz ftrace_graph_caller - - cmpq $ftrace_graph_entry_stub, ftrace_graph_entry - jnz ftrace_graph_caller -#endif - -GLOBAL(ftrace_stub) - retq - -trace: - MCOUNT_SAVE_FRAME - - movq RIP(%rsp), %rdi -#ifdef CC_USING_FENTRY - movq SS+16(%rsp), %rsi -#else - movq 8(%rbp), %rsi -#endif - subq $MCOUNT_INSN_SIZE, %rdi - - call *ftrace_trace_function - - MCOUNT_RESTORE_FRAME - - jmp ftrace_stub -END(function_hook) -#endif /* CONFIG_DYNAMIC_FTRACE */ -#endif /* CONFIG_FUNCTION_TRACER */ - -#ifdef CONFIG_FUNCTION_GRAPH_TRACER -ENTRY(ftrace_graph_caller) - MCOUNT_SAVE_FRAME - -#ifdef CC_USING_FENTRY - leaq SS+16(%rsp), %rdi - movq $0, %rdx /* No framepointers needed */ -#else - leaq 8(%rbp), %rdi - movq (%rbp), %rdx -#endif - movq RIP(%rsp), %rsi - subq $MCOUNT_INSN_SIZE, %rsi - - call prepare_ftrace_return - - MCOUNT_RESTORE_FRAME - - retq -END(ftrace_graph_caller) - -GLOBAL(return_to_handler) - subq $24, %rsp - - /* Save the return values */ - movq %rax, (%rsp) - movq %rdx, 8(%rsp) - movq %rbp, %rdi - - call ftrace_return_to_handler - - movq %rax, %rdi - movq 8(%rsp), %rdx - movq (%rsp), %rax - addq $24, %rsp - jmp *%rdi -#endif - #ifndef CONFIG_PREEMPT #define retint_kernel retint_restore_args diff --git a/arch/x86/kernel/mcount_64.S b/arch/x86/kernel/mcount_64.S new file mode 100644 index 000000000000..c050a0153168 --- /dev/null +++ b/arch/x86/kernel/mcount_64.S @@ -0,0 +1,217 @@ +/* + * linux/arch/x86_64/mcount_64.S + * + * Copyright (C) 2014 Steven Rostedt, Red Hat Inc + */ + +#include +#include +#include + + + .code64 + .section .entry.text, "ax" + + +#ifdef CONFIG_FUNCTION_TRACER + +#ifdef CC_USING_FENTRY +# define function_hook __fentry__ +#else +# define function_hook mcount +#endif + +#ifdef CONFIG_DYNAMIC_FTRACE + +ENTRY(function_hook) + retq +END(function_hook) + +/* skip is set if stack has been adjusted */ +.macro ftrace_caller_setup skip=0 + MCOUNT_SAVE_FRAME \skip + + /* Load the ftrace_ops into the 3rd parameter */ + movq function_trace_op(%rip), %rdx + + /* Load ip into the first parameter */ + movq RIP(%rsp), %rdi + subq $MCOUNT_INSN_SIZE, %rdi + /* Load the parent_ip into the second parameter */ +#ifdef CC_USING_FENTRY + movq SS+16(%rsp), %rsi +#else + movq 8(%rbp), %rsi +#endif +.endm + +ENTRY(ftrace_caller) + /* Check if tracing was disabled (quick check) */ + cmpl $0, function_trace_stop + jne ftrace_stub + + ftrace_caller_setup + /* regs go into 4th parameter (but make it NULL) */ + movq $0, %rcx + +GLOBAL(ftrace_call) + call ftrace_stub + + MCOUNT_RESTORE_FRAME +ftrace_return: + +#ifdef CONFIG_FUNCTION_GRAPH_TRACER +GLOBAL(ftrace_graph_call) + jmp ftrace_stub +#endif + +GLOBAL(ftrace_stub) + retq +END(ftrace_caller) + +ENTRY(ftrace_regs_caller) + /* Save the current flags before compare (in SS location)*/ + pushfq + + /* Check if tracing was disabled (quick check) */ + cmpl $0, function_trace_stop + jne ftrace_restore_flags + + /* skip=8 to skip flags saved in SS */ + ftrace_caller_setup 8 + + /* Save the rest of pt_regs */ + movq %r15, R15(%rsp) + movq %r14, R14(%rsp) + movq %r13, R13(%rsp) + movq %r12, R12(%rsp) + movq %r11, R11(%rsp) + movq %r10, R10(%rsp) + movq %rbp, RBP(%rsp) + movq %rbx, RBX(%rsp) + /* Copy saved flags */ + movq SS(%rsp), %rcx + movq %rcx, EFLAGS(%rsp) + /* Kernel segments */ + movq $__KERNEL_DS, %rcx + movq %rcx, SS(%rsp) + movq $__KERNEL_CS, %rcx + movq %rcx, CS(%rsp) + /* Stack - skipping return address */ + leaq SS+16(%rsp), %rcx + movq %rcx, RSP(%rsp) + + /* regs go into 4th parameter */ + leaq (%rsp), %rcx + +GLOBAL(ftrace_regs_call) + call ftrace_stub + + /* Copy flags back to SS, to restore them */ + movq EFLAGS(%rsp), %rax + movq %rax, SS(%rsp) + + /* Handlers can change the RIP */ + movq RIP(%rsp), %rax + movq %rax, SS+8(%rsp) + + /* restore the rest of pt_regs */ + movq R15(%rsp), %r15 + movq R14(%rsp), %r14 + movq R13(%rsp), %r13 + movq R12(%rsp), %r12 + movq R10(%rsp), %r10 + movq RBP(%rsp), %rbp + movq RBX(%rsp), %rbx + + /* skip=8 to skip flags saved in SS */ + MCOUNT_RESTORE_FRAME 8 + + /* Restore flags */ + popfq + + jmp ftrace_return +ftrace_restore_flags: + popfq + jmp ftrace_stub + +END(ftrace_regs_caller) + + +#else /* ! CONFIG_DYNAMIC_FTRACE */ + +ENTRY(function_hook) + cmpl $0, function_trace_stop + jne ftrace_stub + + cmpq $ftrace_stub, ftrace_trace_function + jnz trace + +#ifdef CONFIG_FUNCTION_GRAPH_TRACER + cmpq $ftrace_stub, ftrace_graph_return + jnz ftrace_graph_caller + + cmpq $ftrace_graph_entry_stub, ftrace_graph_entry + jnz ftrace_graph_caller +#endif + +GLOBAL(ftrace_stub) + retq + +trace: + MCOUNT_SAVE_FRAME + + movq RIP(%rsp), %rdi +#ifdef CC_USING_FENTRY + movq SS+16(%rsp), %rsi +#else + movq 8(%rbp), %rsi +#endif + subq $MCOUNT_INSN_SIZE, %rdi + + call *ftrace_trace_function + + MCOUNT_RESTORE_FRAME + + jmp ftrace_stub +END(function_hook) +#endif /* CONFIG_DYNAMIC_FTRACE */ +#endif /* CONFIG_FUNCTION_TRACER */ + +#ifdef CONFIG_FUNCTION_GRAPH_TRACER +ENTRY(ftrace_graph_caller) + MCOUNT_SAVE_FRAME + +#ifdef CC_USING_FENTRY + leaq SS+16(%rsp), %rdi + movq $0, %rdx /* No framepointers needed */ +#else + leaq 8(%rbp), %rdi + movq (%rbp), %rdx +#endif + movq RIP(%rsp), %rsi + subq $MCOUNT_INSN_SIZE, %rsi + + call prepare_ftrace_return + + MCOUNT_RESTORE_FRAME + + retq +END(ftrace_graph_caller) + +GLOBAL(return_to_handler) + subq $24, %rsp + + /* Save the return values */ + movq %rax, (%rsp) + movq %rdx, 8(%rsp) + movq %rbp, %rdi + + call ftrace_return_to_handler + + movq %rax, %rdi + movq 8(%rsp), %rdx + movq (%rsp), %rax + addq $24, %rsp + jmp *%rdi +#endif -- cgit v1.2.2 From 964f7b6b785651a75ef1cbad43a393ca52d4b4f7 Mon Sep 17 00:00:00 2001 From: Petr Mladek Date: Tue, 3 Jun 2014 18:23:21 +0200 Subject: ftrace/x86: Call text_ip_addr() instead of the duplicated code I just went over this when looking at some Xen-related ftrace initialization problems. They were related to Xen code that is not upstream but this clean up would make sense here. I think that this was already the intention when text_ip_addr() was introduced in the commit 87fbb2ac6073a703930 (ftrace/x86: Use breakpoints for converting function graph caller). Anyway, better do it now before it shots people into their leg ;-) Link: http://lkml.kernel.org/p/1401812601-2359-1-git-send-email-pmladek@suse.cz Signed-off-by: Petr Mladek Signed-off-by: Steven Rostedt --- arch/x86/kernel/ftrace.c | 11 +---------- 1 file changed, 1 insertion(+), 10 deletions(-) (limited to 'arch/x86') diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c index 89de3eaf8772..cbc4a91b131e 100644 --- a/arch/x86/kernel/ftrace.c +++ b/arch/x86/kernel/ftrace.c @@ -297,16 +297,7 @@ int ftrace_int3_handler(struct pt_regs *regs) static int ftrace_write(unsigned long ip, const char *val, int size) { - /* - * On x86_64, kernel text mappings are mapped read-only with - * CONFIG_DEBUG_RODATA. So we use the kernel identity mapping instead - * of the kernel text mapping to modify the kernel text. - * - * For 32bit kernels, these mappings are same and we can use - * kernel identity mapping to modify code. - */ - if (within(ip, (unsigned long)_text, (unsigned long)_etext)) - ip = (unsigned long)__va(__pa_symbol(ip)); + ip = text_ip_addr(ip); if (probe_kernel_write((void *)ip, val, size)) return -EPERM; -- cgit v1.2.2