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ANDROID: arm64: Fix the address of ftrace_call compiled with CFI_CLANG

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When CONFIG_CFI_CLANG and CONFIG_DYNAMIC_FTRACE are enabled, LLVM will
generate a jump function named ftrace_call.cfi_jt for ftrace_call, which
makes "&ftrace_call" in ftrace_update_ftrace_func() actually the address
of ftrace_call.cfi_jt. As a result, the tracer can't be really enabled
through runtime modification. Use __va_function() to get the actual address
of ftrace_call to fix the issue.

Bug: 184105181
Signed-off-by: Ben Dai <ben.dai@unisoc.com>
Change-Id: Ic9272cd4ab447b3b145d8e397e5c9010c49f7a12
This commit is contained in:
Ben Dai
2021-03-31 09:29:17 +08:00
committed by Bruno Martins
parent cee0aa0c31
commit 9bafb37470
1 changed files with 1 additions and 1 deletions
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2
arch/arm64/kernel/ftrace.c
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@@ -58,7 +58,7 @@ int ftrace_update_ftrace_func(ftrace_func_t func)
unsigned long pc;
u32 new;
pc = (unsigned long)&ftrace_call;
pc = (unsigned long)__va_function(ftrace_call);
new = aarch64_insn_gen_branch_imm(pc, (unsigned long)func,
AARCH64_INSN_BRANCH_LINK);