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author | Mark Rutland <mark.rutland@arm.com> | 2017-06-23 18:02:06 +0100 |
---|---|---|
committer | Will Deacon <will.deacon@arm.com> | 2017-06-23 18:21:13 +0100 |
commit | 8486e54d30e170c969090f80bbdfa7142d33ed6a (patch) | |
tree | beae3c73a6ca47ceafc6803ff15459f3a2badcb1 /arch/arm64/kernel/ftrace.c | |
parent | 33f082614c3443d937f50fe936f284f62bbb4a1b (diff) | |
download | linux-stable-8486e54d30e170c969090f80bbdfa7142d33ed6a.tar.gz linux-stable-8486e54d30e170c969090f80bbdfa7142d33ed6a.tar.bz2 linux-stable-8486e54d30e170c969090f80bbdfa7142d33ed6a.zip |
arm64: ftrace: fix !CONFIG_ARM64_MODULE_PLTS kernels
When a kernel is built without CONFIG_ARM64_MODULE_PLTS, we don't
generate the expected branch instruction in ftrace_make_nop(). This
means we pass zero (rather than a valid branch) to ftrace_modify_code()
as the expected instruction to validate. This causes us to return
-EINVAL to the core ftrace code for a valid case, resulting in a splat
at boot time.
This was an unintended effect of commit:
687644209a6e9557 ("arm64: ftrace: fix building without CONFIG_MODULES")
... which incorrectly moved the generation of the branch instruction
into the ifdef for CONFIG_ARM64_MODULE_PLTS.
This patch fixes the issue by moving the ifdef inside of the relevant
if-else case, and always checking that the branch is in range,
regardless of CONFIG_ARM64_MODULE_PLTS. This ensures that we generate
the expected branch instruction, and also improves our sanity checks.
For consistency, both ftrace_make_nop() and ftrace_make_call() are
updated with this pattern.
Fixes: 687644209a6e9557 ("arm64: ftrace: fix building without CONFIG_MODULES")
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reported-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Diffstat (limited to 'arch/arm64/kernel/ftrace.c')
-rw-r--r-- | arch/arm64/kernel/ftrace.c | 14 |
1 files changed, 8 insertions, 6 deletions
diff --git a/arch/arm64/kernel/ftrace.c b/arch/arm64/kernel/ftrace.c index 401aa27808a4..c13b1fca0e5b 100644 --- a/arch/arm64/kernel/ftrace.c +++ b/arch/arm64/kernel/ftrace.c @@ -72,11 +72,10 @@ int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) { unsigned long pc = rec->ip; u32 old, new; - -#ifdef CONFIG_ARM64_MODULE_PLTS long offset = (long)pc - (long)addr; if (offset < -SZ_128M || offset >= SZ_128M) { +#ifdef CONFIG_ARM64_MODULE_PLTS unsigned long *trampoline; struct module *mod; @@ -121,8 +120,10 @@ int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) smp_wmb(); } addr = (unsigned long)&trampoline[1]; - } +#else /* CONFIG_ARM64_MODULE_PLTS */ + return -EINVAL; #endif /* CONFIG_ARM64_MODULE_PLTS */ + } old = aarch64_insn_gen_nop(); new = aarch64_insn_gen_branch_imm(pc, addr, AARCH64_INSN_BRANCH_LINK); @@ -139,11 +140,10 @@ int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, unsigned long pc = rec->ip; bool validate = true; u32 old = 0, new; - -#ifdef CONFIG_ARM64_MODULE_PLTS long offset = (long)pc - (long)addr; if (offset < -SZ_128M || offset >= SZ_128M) { +#ifdef CONFIG_ARM64_MODULE_PLTS u32 replaced; /* @@ -176,11 +176,13 @@ int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, return -EINVAL; validate = false; +#else /* CONFIG_ARM64_MODULE_PLTS */ + return -EINVAL; +#endif /* CONFIG_ARM64_MODULE_PLTS */ } else { old = aarch64_insn_gen_branch_imm(pc, addr, AARCH64_INSN_BRANCH_LINK); } -#endif /* CONFIG_ARM64_MODULE_PLTS */ new = aarch64_insn_gen_nop(); |