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authorMarcin Nowakowski <marcin.nowakowski@imgtec.com>2017-05-23 12:56:43 +0200
committerRalf Baechle <ralf@linux-mips.org>2017-06-08 14:51:59 +0200
commit87051ec120bb9abd9e57aecf2569c00d587b6f33 (patch)
tree1122c249e13dcfee286d7807f4625a74da19e079 /arch
parentc56e7a4c3e77f6fbd9b55c06c14eda65aae58958 (diff)
downloadlinux-87051ec120bb9abd9e57aecf2569c00d587b6f33.tar.bz2
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.c24
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 */