2022-11-26 06:35:21

by Samuel Holland

[permalink] [raw]
Subject: [PATCH v2 1/2] riscv: Fix crash during early errata patching

The patch function for the T-Head PBMT errata calls __pa_symbol() before
relocation. This crashes when CONFIG_DEBUG_VIRTUAL is enabled, because
__pa_symbol() forwards to __phys_addr_symbol(), and __phys_addr_symbol()
checks against the absolute kernel start/end address.

Fix this by checking against the kernel map instead of a symbol address.

Fixes: a35707c3d850 ("riscv: add memory-type errata for T-Head")
Reviewed-by: Heiko Stuebner <[email protected]>
Tested-by: Heiko Stuebner <[email protected]>
Signed-off-by: Samuel Holland <[email protected]>
---

Changes in v2:
- Fix __phys_addr_symbol instead of avoiding it in the errata code

arch/riscv/mm/physaddr.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/riscv/mm/physaddr.c b/arch/riscv/mm/physaddr.c
index 19cf25a74ee2..9b18bda74154 100644
--- a/arch/riscv/mm/physaddr.c
+++ b/arch/riscv/mm/physaddr.c
@@ -22,7 +22,7 @@ EXPORT_SYMBOL(__virt_to_phys);
phys_addr_t __phys_addr_symbol(unsigned long x)
{
unsigned long kernel_start = kernel_map.virt_addr;
- unsigned long kernel_end = (unsigned long)_end;
+ unsigned long kernel_end = kernel_start + kernel_map.size;

/*
* Boundary checking aginst the kernel image mapping.
--
2.37.4


Subject: Re: [PATCH v2 1/2] riscv: Fix crash during early errata patching

Hello:

This series was applied to riscv/linux.git (for-next)
by Palmer Dabbelt <[email protected]>:

On Sat, 26 Nov 2022 00:09:19 -0600 you wrote:
> The patch function for the T-Head PBMT errata calls __pa_symbol() before
> relocation. This crashes when CONFIG_DEBUG_VIRTUAL is enabled, because
> __pa_symbol() forwards to __phys_addr_symbol(), and __phys_addr_symbol()
> checks against the absolute kernel start/end address.
>
> Fix this by checking against the kernel map instead of a symbol address.
>
> [...]

Here is the summary with links:
- [v2,1/2] riscv: Fix crash during early errata patching
https://git.kernel.org/riscv/c/61b2f0bdaa3c
- [v2,2/2] riscv: Move cast inside kernel_mapping_[pv]a_to_[vp]a
https://git.kernel.org/riscv/c/583286e2072e

You are awesome, thank you!
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