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riscv: ftrace: Add DYNAMIC_FTRACE_WITH_DIRECT_CALLS support

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Select the DYNAMIC_FTRACE_WITH_DIRECT_CALLS to provide the
register_ftrace_direct[_multi] interfaces allowing users to register
the customed trampoline (direct_caller) as the mcount for one or more
target functions. And modify_ftrace_direct[_multi] are also provided
for modifying direct_caller.

To make the direct_caller and the other ftrace hooks (e.g.
function/fgraph tracer, k[ret]probes) co-exist, a temporary register
is nominated to store the address of direct_caller in
ftrace_regs_caller. After the setting of the address direct_caller by
direct_ops->func and the RESTORE_REGS in ftrace_regs_caller,
direct_caller will be jumped to by the `jr` inst.

Add DYNAMIC_FTRACE_WITH_DIRECT_CALLS support for RISC-V.

Signed-off-by: Song Shuai <suagrfillet@gmail.com>
Tested-by: Guo Ren <guoren@kernel.org>
Signed-off-by: Guo Ren <guoren@kernel.org>
Acked-by: Björn Töpel <bjorn@rivosinc.com>
Link: https://lore.kernel.org/r/20231130121531.1178502-4-bjorn@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
This commit is contained in:
Song Shuai
2023-11-30 13:15:30 +01:00
committed by Palmer Dabbelt
parent 35e61e8827
commit 196c79f19a
3 changed files with 18 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files
arch/riscv/Kconfig
+1
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@@ -114,6 +114,7 @@ config RISCV
select HAVE_DEBUG_KMEMLEAK
select HAVE_DMA_CONTIGUOUS if MMU
select HAVE_DYNAMIC_FTRACE if !XIP_KERNEL && MMU && (CLANG_SUPPORTS_DYNAMIC_FTRACE || GCC_SUPPORTS_DYNAMIC_FTRACE)
select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
select HAVE_DYNAMIC_FTRACE_WITH_REGS if HAVE_DYNAMIC_FTRACE
select HAVE_FTRACE_MCOUNT_RECORD if !XIP_KERNEL
select HAVE_FUNCTION_GRAPH_TRACER
arch/riscv/include/asm/ftrace.h
+7
View File
@@ -135,6 +135,13 @@ struct ftrace_regs;
void ftrace_graph_func(unsigned long ip, unsigned long parent_ip,
struct ftrace_ops *op, struct ftrace_regs *fregs);
#define ftrace_graph_func ftrace_graph_func
static inline void __arch_ftrace_set_direct_caller(struct pt_regs *regs, unsigned long addr)
{
regs->t1 = addr;
}
#define arch_ftrace_set_direct_caller(fregs, addr) \
__arch_ftrace_set_direct_caller(&(fregs)->regs, addr)
#endif /* CONFIG_DYNAMIC_FTRACE_WITH_REGS */
#endif /* __ASSEMBLY__ */
arch/riscv/kernel/mcount-dyn.S
+10
View File
@@ -229,6 +229,7 @@ SYM_FUNC_END(ftrace_caller)
#else /* CONFIG_DYNAMIC_FTRACE_WITH_REGS */
SYM_FUNC_START(ftrace_regs_caller)
mv t1, zero
SAVE_ABI_REGS 1
PREPARE_ARGS
@@ -236,7 +237,10 @@ SYM_INNER_LABEL(ftrace_regs_call, SYM_L_GLOBAL)
call ftrace_stub
RESTORE_ABI_REGS 1
bnez t1, .Ldirect
jr t0
.Ldirect:
jr t1
SYM_FUNC_END(ftrace_regs_caller)
SYM_FUNC_START(ftrace_caller)
@@ -250,3 +254,9 @@ SYM_INNER_LABEL(ftrace_call, SYM_L_GLOBAL)
jr t0
SYM_FUNC_END(ftrace_caller)
#endif /* CONFIG_DYNAMIC_FTRACE_WITH_REGS */
#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
SYM_CODE_START(ftrace_stub_direct_tramp)
jr t0
SYM_CODE_END(ftrace_stub_direct_tramp)
#endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */