| Message ID | 20240628-dev-andyc-dyn-ftrace-v4-v2-1-1e5f4cb1f049@sifive.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Headers | show |
| Series | riscv: ftrace: atmoic patching and preempt improvements | expand |
Andy Chiu <andy.chiu@sifive.com> writes: > 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/ > Acked-by: Nathan Chancellor <nathan@kernel.org> > Signed-off-by: Andy Chiu <andy.chiu@sifive.com> Shouldn't this be a separate fix? Still reading the details, but it smells like something what should be disabled when building w/ LLVM, no? Björn
On Tue, Aug 13, 2024 at 7:09 PM Björn Töpel <bjorn@kernel.org> wrote: > > Andy Chiu <andy.chiu@sifive.com> writes: > > > 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/ > > Acked-by: Nathan Chancellor <nathan@kernel.org> > > Signed-off-by: Andy Chiu <andy.chiu@sifive.com> > > Shouldn't this be a separate fix? Still reading the details, but it > smells like something what should be disabled when building w/ LLVM, no? Yes, this is a fix. My intention was indicating the dependency. So people won't hit into trouble testing it. I can send it in a separate series. Thanks, Andy
diff --git a/arch/riscv/include/asm/ftrace.h b/arch/riscv/include/asm/ftrace.h index 9eb31a7ea0aa..5f81c53dbfd9 100644 --- a/arch/riscv/include/asm/ftrace.h +++ b/arch/riscv/include/asm/ftrace.h @@ -144,6 +144,13 @@ struct 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 }; }; }; diff --git a/arch/riscv/kernel/asm-offsets.c b/arch/riscv/kernel/asm-offsets.c index b09ca5f944f7..db5a26fcc9ae 100644 --- a/arch/riscv/kernel/asm-offsets.c +++ b/arch/riscv/kernel/asm-offsets.c @@ -497,6 +497,13 @@ void asm_offsets(void) DEFINE(FREGS_SP, offsetof(struct ftrace_regs, sp)); DEFINE(FREGS_S0, offsetof(struct ftrace_regs, s0)); DEFINE(FREGS_T1, offsetof(struct ftrace_regs, t1)); +#ifdef CONFIG_CC_IS_CLANG + DEFINE(FREGS_T2, offsetof(struct ftrace_regs, t2)); + DEFINE(FREGS_T3, offsetof(struct ftrace_regs, t3)); + DEFINE(FREGS_T4, offsetof(struct ftrace_regs, t4)); + DEFINE(FREGS_T5, offsetof(struct ftrace_regs, t5)); + DEFINE(FREGS_T6, offsetof(struct ftrace_regs, t6)); +#endif DEFINE(FREGS_A0, offsetof(struct ftrace_regs, a0)); DEFINE(FREGS_A1, offsetof(struct ftrace_regs, a1)); DEFINE(FREGS_A2, offsetof(struct ftrace_regs, a2)); diff --git a/arch/riscv/kernel/mcount-dyn.S b/arch/riscv/kernel/mcount-dyn.S index 745dd4c4a69c..e988bd26b28b 100644 --- a/arch/riscv/kernel/mcount-dyn.S +++ b/arch/riscv/kernel/mcount-dyn.S @@ -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)