| Message ID | 20240506022239.6817-1-gaoshanliukou@163.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [V2] riscv: set trap vector earlier | expand |
Hi Yang, On 06/05/2024 04:22, yang.zhang wrote: > From: "yang.zhang" <yang.zhang@hexintek.com> > > If trap earlier, trap vector doesn't yet set properly, current > value maybe set by previous firmwire, typically it's the _start of kernel, > it's confused and difficult to debuge, so set it earlier. What about: "The exception vector of the booting hart is not set before enabling the mmu and then still points to the value of the previous firmware, typically _start_kernel. That makes it hard to debug setup_vm() when bad things happen. So fix that by setting the exception vector earlier." > --- > v1 -> v2: > As Alex commented, remove the patch for supporting hugesize kernek image > Add the omissive logic of set trap vector earlier > > Signed-off-by: yang.zhang <yang.zhang@hexintek.com> > --- > arch/riscv/kernel/head.S | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S > index 4236a69c35cb..03dc440e643e 100644 > --- a/arch/riscv/kernel/head.S > +++ b/arch/riscv/kernel/head.S > @@ -300,6 +300,9 @@ SYM_CODE_START(_start_kernel) > #else > mv a0, a1 > #endif /* CONFIG_BUILTIN_DTB */ > + /* Set trap vector to spin forever to help debug */ > + la a3, .Lsecondary_park > + csrw CSR_TVEC, a3 > call setup_vm > #ifdef CONFIG_MMU > la a0, early_pg_dir Note that this patch will allow to catch any exception happening in setup_vm() but as we reset stvec in relocate_enable_mmu. But that's ok, it will help catching weird bugs more easily :) With the commit message fixed, you can add: Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com> Thanks, Alex
At 2024-05-07 13:28:58, "Alexandre Ghiti" <alex@ghiti.fr> wrote: >Hi Yang, > >On 06/05/2024 04:22, yang.zhang wrote: >> From: "yang.zhang" <yang.zhang@hexintek.com> >> >> If trap earlier, trap vector doesn't yet set properly, current >> value maybe set by previous firmwire, typically it's the _start of kernel, >> it's confused and difficult to debuge, so set it earlier. > > >What about: > >"The exception vector of the booting hart is not set before enabling the >mmu and then still points to the value of the previous firmware, >typically _start_kernel. That makes it hard to debug setup_vm() when bad >things happen. So fix that by setting the exception vector earlier." Hi alex: Maybe "typically _start" not "typically _start_kernel", right? Thanks for your help。 >> --- >> v1 -> v2: >> As Alex commented, remove the patch for supporting hugesize kernek image >> Add the omissive logic of set trap vector earlier >> >> Signed-off-by: yang.zhang <yang.zhang@hexintek.com> >> --- >> arch/riscv/kernel/head.S | 3 +++ >> 1 file changed, 3 insertions(+) >> >> diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S >> index 4236a69c35cb..03dc440e643e 100644 >> --- a/arch/riscv/kernel/head.S >> +++ b/arch/riscv/kernel/head.S >> @@ -300,6 +300,9 @@ SYM_CODE_START(_start_kernel) >> #else >> mv a0, a1 >> #endif /* CONFIG_BUILTIN_DTB */ >> + /* Set trap vector to spin forever to help debug */ >> + la a3, .Lsecondary_park >> + csrw CSR_TVEC, a3 >> call setup_vm >> #ifdef CONFIG_MMU >> la a0, early_pg_dir > >Note that this patch will allow to catch any exception happening in >setup_vm() but as we reset stvec in relocate_enable_mmu. But that's ok, >it will help catching weird bugs more easily :) > >With the commit message fixed, you can add: > >Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com> > >Thanks, > >Alex
diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S index 4236a69c35cb..03dc440e643e 100644 --- a/arch/riscv/kernel/head.S +++ b/arch/riscv/kernel/head.S @@ -300,6 +300,9 @@ SYM_CODE_START(_start_kernel) #else mv a0, a1 #endif /* CONFIG_BUILTIN_DTB */ + /* Set trap vector to spin forever to help debug */ + la a3, .Lsecondary_park + csrw CSR_TVEC, a3 call setup_vm #ifdef CONFIG_MMU la a0, early_pg_dir