Messages in this thread Patch in this message | | | From | Mark Rutland <> | Subject | [PATCH v2 6/8] arm64: patching: Add aarch64_insn_write_literal_u64() | Date | Fri, 13 Jan 2023 18:03:53 +0000 |
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In subsequent patches we'll need to atomically write to a naturally-aligned 64-bit literal embedded within the kernel text.
Add a helper for this. For consistency with other text patching code we use copy_to_kernel_nofault(), which is atomic for naturally-aligned accesses up to 64-bits.
Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Florent Revest <revest@chromium.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Will Deacon <will@kernel.org> --- arch/arm64/include/asm/patching.h | 2 ++ arch/arm64/kernel/patching.c | 17 +++++++++++++++++ 2 files changed, 19 insertions(+)
diff --git a/arch/arm64/include/asm/patching.h b/arch/arm64/include/asm/patching.h index 6bf5adc56295..68908b82b168 100644 --- a/arch/arm64/include/asm/patching.h +++ b/arch/arm64/include/asm/patching.h @@ -7,6 +7,8 @@ int aarch64_insn_read(void *addr, u32 *insnp); int aarch64_insn_write(void *addr, u32 insn); +int aarch64_insn_write_literal_u64(void *addr, u64 val); + int aarch64_insn_patch_text_nosync(void *addr, u32 insn); int aarch64_insn_patch_text(void *addrs[], u32 insns[], int cnt); diff --git a/arch/arm64/kernel/patching.c b/arch/arm64/kernel/patching.c index 33e0fabc0b79..b4835f6d594b 100644 --- a/arch/arm64/kernel/patching.c +++ b/arch/arm64/kernel/patching.c @@ -88,6 +88,23 @@ int __kprobes aarch64_insn_write(void *addr, u32 insn) return __aarch64_insn_write(addr, cpu_to_le32(insn)); } +noinstr int aarch64_insn_write_literal_u64(void *addr, u64 val) +{ + u64 *waddr; + unsigned long flags; + int ret; + + raw_spin_lock_irqsave(&patch_lock, flags); + waddr = patch_map(addr, FIX_TEXT_POKE0); + + ret = copy_to_kernel_nofault(waddr, &val, sizeof(val)); + + patch_unmap(FIX_TEXT_POKE0); + raw_spin_unlock_irqrestore(&patch_lock, flags); + + return ret; +} + int __kprobes aarch64_insn_patch_text_nosync(void *addr, u32 insn) { u32 *tp = addr; -- 2.30.2
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