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| author | Marcin Nowakowski <marcin.nowakowski@imgtec.com> | 2017-05-23 12:56:43 +0200 |
|---|---|---|
| committer | Ralf Baechle <ralf@linux-mips.org> | 2017-06-08 14:51:59 +0200 |
| commit | 87051ec120bb9abd9e57aecf2569c00d587b6f33 (patch) | |
| tree | 1122c249e13dcfee286d7807f4625a74da19e079 /arch | |
| parent | c56e7a4c3e77f6fbd9b55c06c14eda65aae58958 (diff) | |
| download | linux-87051ec120bb9abd9e57aecf2569c00d587b6f33.tar.gz linux-87051ec120bb9abd9e57aecf2569c00d587b6f33.tar.bz2 linux-87051ec120bb9abd9e57aecf2569c00d587b6f33.zip | |
MIPS: ftrace: fix init functions tracing
Since introduction of tracing for init functions the in_kernel_space()
check is no longer correct, as it ignores the init sections. As a
result, when probes are inserted (and disabled) in the init functions,
a branch instruction is inserted instead of a nop, which is likely to
result in random crashes during boot.
Remove the MIPS-specific in_kernel_space() method and replace it with a
generic core_kernel_text() that also checks for init sections during
system boot stage.
Fixes: 42c269c88dc1 ("ftrace: Allow for function tracing to record init functions on boot up")
Signed-off-by: Marcin Nowakowski <marcin.nowakowski@imgtec.com>
Tested-by: Matt Redfearn <matt.redfearn@imgtec.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/16092/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/mips/kernel/ftrace.c | 24 |
1 files changed, 5 insertions, 19 deletions
diff --git a/arch/mips/kernel/ftrace.c b/arch/mips/kernel/ftrace.c index 30a3b75e88eb..9d9b8fbae202 100644 --- a/arch/mips/kernel/ftrace.c +++ b/arch/mips/kernel/ftrace.c @@ -38,20 +38,6 @@ void arch_ftrace_update_code(int command) #endif -/* - * Check if the address is in kernel space - * - * Clone core_kernel_text() from kernel/extable.c, but doesn't call - * init_kernel_text() for Ftrace doesn't trace functions in init sections. - */ -static inline int in_kernel_space(unsigned long ip) -{ - if (ip >= (unsigned long)_stext && - ip <= (unsigned long)_etext) - return 1; - return 0; -} - #ifdef CONFIG_DYNAMIC_FTRACE #define JAL 0x0c000000 /* jump & link: ip --> ra, jump to target */ @@ -198,7 +184,7 @@ int ftrace_make_nop(struct module *mod, * If ip is in kernel space, no long call, otherwise, long call is * needed. */ - new = in_kernel_space(ip) ? INSN_NOP : INSN_B_1F; + new = core_kernel_text(ip) ? INSN_NOP : INSN_B_1F; #ifdef CONFIG_64BIT return ftrace_modify_code(ip, new); #else @@ -218,12 +204,12 @@ int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) unsigned int new; unsigned long ip = rec->ip; - new = in_kernel_space(ip) ? insn_jal_ftrace_caller : insn_la_mcount[0]; + new = core_kernel_text(ip) ? insn_jal_ftrace_caller : insn_la_mcount[0]; #ifdef CONFIG_64BIT return ftrace_modify_code(ip, new); #else - return ftrace_modify_code_2r(ip, new, in_kernel_space(ip) ? + return ftrace_modify_code_2r(ip, new, core_kernel_text(ip) ? INSN_NOP : insn_la_mcount[1]); #endif } @@ -289,7 +275,7 @@ unsigned long ftrace_get_parent_ra_addr(unsigned long self_ra, unsigned long * instruction "lui v1, hi_16bit_of_mcount"(offset is 24), but for * kernel, move after the instruction "move ra, at"(offset is 16) */ - ip = self_ra - (in_kernel_space(self_ra) ? 16 : 24); + ip = self_ra - (core_kernel_text(self_ra) ? 16 : 24); /* * search the text until finding the non-store instruction or "s{d,w} @@ -394,7 +380,7 @@ void prepare_ftrace_return(unsigned long *parent_ra_addr, unsigned long self_ra, * entries configured through the tracing/set_graph_function interface. */ - insns = in_kernel_space(self_ra) ? 2 : MCOUNT_OFFSET_INSNS + 1; + insns = core_kernel_text(self_ra) ? 2 : MCOUNT_OFFSET_INSNS + 1; trace.func = self_ra - (MCOUNT_INSN_SIZE * insns); /* Only trace if the calling function expects to */ |