linux-kernel - [PATCH 1/2] riscv: Fix crash during early errata patching

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Date:   Thu, 22 Sep 2022 00:47:41 -0500
From:   Samuel Holland <samuel@...lland.org>
To:     Palmer Dabbelt <palmer@...belt.com>,
        linux-riscv@...ts.infradead.org
Cc:     Samuel Holland <samuel@...lland.org>,
        Albert Ou <aou@...s.berkeley.edu>, Guo Ren <guoren@...nel.org>,
        Heiko Stuebner <heiko@...ech.de>,
        Paul Walmsley <paul.walmsley@...ive.com>,
        linux-kernel@...r.kernel.org
Subject: [PATCH 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 directly using the underlying kernel_mapping_va_to_pa().

Fixes: a35707c3d850 ("riscv: add memory-type errata for T-Head")
Signed-off-by: Samuel Holland <samuel@...lland.org>
---

 arch/riscv/errata/thead/errata.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/riscv/errata/thead/errata.c b/arch/riscv/errata/thead/errata.c
index 202c83f677b2..83174f13783e 100644
--- a/arch/riscv/errata/thead/errata.c
+++ b/arch/riscv/errata/thead/errata.c
@@ -76,8 +76,9 @@ void __init_or_module thead_errata_patch_func(struct alt_entry *begin, struct al
 		if (cpu_req_errata & tmp) {
 			/* On vm-alternatives, the mmu isn't running yet */
 			if (stage == RISCV_ALTERNATIVES_EARLY_BOOT)
-				memcpy((void *)__pa_symbol(alt->old_ptr),
-				       (void *)__pa_symbol(alt->alt_ptr), alt->alt_len);
+				memcpy((void *)kernel_mapping_va_to_pa((unsigned long)alt->old_ptr),
+				       (void *)kernel_mapping_va_to_pa((unsigned long)alt->alt_ptr),
+				       alt->alt_len);
 			else
 				patch_text_nosync(alt->old_ptr, alt->alt_ptr, alt->alt_len);
 		}
-- 
2.35.1