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riscv: ftrace: support fastcc in Clang for WITH_ARGS

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Some caller-saved registers which are not defined as function arguments
in the ABI can still be passed as arguments when the kernel is compiled
with Clang. As a result, we must save and restore those registers to
prevent ftrace from clobbering them.

- [1]: https://reviews.llvm.org/D68559

Reported-by: Evgenii Shatokhin <e.shatokhin@yadro.com>
Closes: https://lore.kernel.org/linux-riscv/7e7c7914-445d-426d-89a0-59a9199c45b1@yadro.com/
Fixes: 7caa976546 ("ftrace: riscv: move from REGS to ARGS")
Acked-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Björn Töpel <bjorn@rivosinc.com>
Signed-off-by: Andy Chiu <andy.chiu@sifive.com>
Tested-by: Björn Töpel <bjorn@rivosinc.com>
Link: https://lore.kernel.org/r/20250407180838.42877-1-andybnac@gmail.com
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Signed-off-by: Palmer Dabbelt <palmer@dabbelt.com>
This commit is contained in:
Andy Chiu
2025-04-08 02:08:25 +08:00
committed by Palmer Dabbelt
parent 9c32cda43e
commit f8693f6dff
3 changed files with 28 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files

7
arch/riscv/include/asm/ftrace.h
View File

@@ -146,6 +146,13 @@ struct __arch_ftrace_regs {
unsigned long a5;
unsigned long a6;
unsigned long a7;
#ifdef CONFIG_CC_IS_CLANG
unsigned long t2;
unsigned long t3;
unsigned long t4;
unsigned long t5;
unsigned long t6;
#endif
};
};
};

7
arch/riscv/kernel/asm-offsets.c
View File

@@ -501,6 +501,13 @@ void asm_offsets(void)
DEFINE(FREGS_SP, offsetof(struct __arch_ftrace_regs, sp));
DEFINE(FREGS_S0, offsetof(struct __arch_ftrace_regs, s0));
DEFINE(FREGS_T1, offsetof(struct __arch_ftrace_regs, t1));
#ifdef CONFIG_CC_IS_CLANG
DEFINE(FREGS_T2, offsetof(struct __arch_ftrace_regs, t2));
DEFINE(FREGS_T3, offsetof(struct __arch_ftrace_regs, t3));
DEFINE(FREGS_T4, offsetof(struct __arch_ftrace_regs, t4));
DEFINE(FREGS_T5, offsetof(struct __arch_ftrace_regs, t5));
DEFINE(FREGS_T6, offsetof(struct __arch_ftrace_regs, t6));
#endif
DEFINE(FREGS_A0, offsetof(struct __arch_ftrace_regs, a0));
DEFINE(FREGS_A1, offsetof(struct __arch_ftrace_regs, a1));
DEFINE(FREGS_A2, offsetof(struct __arch_ftrace_regs, a2));

16
arch/riscv/kernel/mcount-dyn.S
View File

@@ -96,7 +96,13 @@
REG_S x8, FREGS_S0(sp)
#endif
REG_S x6, FREGS_T1(sp)
#ifdef CONFIG_CC_IS_CLANG
REG_S x7, FREGS_T2(sp)
REG_S x28, FREGS_T3(sp)
REG_S x29, FREGS_T4(sp)
REG_S x30, FREGS_T5(sp)
REG_S x31, FREGS_T6(sp)
#endif
// save the arguments
REG_S x10, FREGS_A0(sp)
REG_S x11, FREGS_A1(sp)
@@ -115,7 +121,13 @@
REG_L x8, FREGS_S0(sp)
#endif
REG_L x6, FREGS_T1(sp)
#ifdef CONFIG_CC_IS_CLANG
REG_L x7, FREGS_T2(sp)
REG_L x28, FREGS_T3(sp)
REG_L x29, FREGS_T4(sp)
REG_L x30, FREGS_T5(sp)
REG_L x31, FREGS_T6(sp)
#endif
// restore the arguments
REG_L x10, FREGS_A0(sp)
REG_L x11, FREGS_A1(sp)