aboutsummaryrefslogtreecommitdiff
path: root/arch/riscv/kernel
diff options
context:
space:
mode:
authorConor Dooley2023-05-12 08:58:18 +0100
committerGreg Kroah-Hartman2023-05-17 11:53:41 +0200
commit0fad198fffdabdeb07f6471f3311a246a9b35e7c (patch)
tree384dc8262feea360e5d72459a69fd3233454d857 /arch/riscv/kernel
parent13a0e212ddefa84586a458de9515a360929fec8f (diff)
RISC-V: take text_mutex during alternative patching
commit 9493e6f3ce02f44c21aa19f3cbf3b9aa05479d06 upstream. Guenter reported a splat during boot, that Samuel pointed out was the lockdep assertion failing in patch_insn_write(): WARNING: CPU: 0 PID: 0 at arch/riscv/kernel/patch.c:63 patch_insn_write+0x222/0x2f6 epc : patch_insn_write+0x222/0x2f6 ra : patch_insn_write+0x21e/0x2f6 epc : ffffffff800068c6 ra : ffffffff800068c2 sp : ffffffff81803df0 gp : ffffffff81a1ab78 tp : ffffffff81814f80 t0 : ffffffffffffe000 t1 : 0000000000000001 t2 : 4c45203a76637369 s0 : ffffffff81803e40 s1 : 0000000000000004 a0 : 0000000000000000 a1 : ffffffffffffffff a2 : 0000000000000004 a3 : 0000000000000000 a4 : 0000000000000001 a5 : 0000000000000000 a6 : 0000000000000000 a7 : 0000000052464e43 s2 : ffffffff80b4889c s3 : 000000000000082c s4 : ffffffff80b48828 s5 : 0000000000000828 s6 : ffffffff8131a0a0 s7 : 0000000000000fff s8 : 0000000008000200 s9 : ffffffff8131a520 s10: 0000000000000018 s11: 000000000000000b t3 : 0000000000000001 t4 : 000000000000000d t5 : ffffffffd8180000 t6 : ffffffff81803bc8 status: 0000000200000100 badaddr: 0000000000000000 cause: 0000000000000003 [<ffffffff800068c6>] patch_insn_write+0x222/0x2f6 [<ffffffff80006a36>] patch_text_nosync+0xc/0x2a [<ffffffff80003b86>] riscv_cpufeature_patch_func+0x52/0x98 [<ffffffff80003348>] _apply_alternatives+0x46/0x86 [<ffffffff80c02d36>] apply_boot_alternatives+0x3c/0xfa [<ffffffff80c03ad8>] setup_arch+0x584/0x5b8 [<ffffffff80c0075a>] start_kernel+0xa2/0x8f8 This issue was exposed by 702e64550b12 ("riscv: fpu: switch has_fpu() to riscv_has_extension_likely()"), as it is the patching in has_fpu() that triggers the splats in Guenter's report. Take the text_mutex before doing any code patching to satisfy lockdep. Fixes: ff689fd21cb1 ("riscv: add RISC-V Svpbmt extension support") Fixes: a35707c3d850 ("riscv: add memory-type errata for T-Head") Fixes: 1a0e5dbd3723 ("riscv: sifive: Add SiFive alternative ports") Reported-by: Guenter Roeck <linux@roeck-us.net> Link: https://lore.kernel.org/all/20230212154333.GA3760469@roeck-us.net/ Signed-off-by: Conor Dooley <conor.dooley@microchip.com> Reviewed-by: Samuel Holland <samuel@sholland.org> Tested-by: Guenter Roeck <linux@roeck-us.net> Link: https://lore.kernel.org/r/20230212194735.491785-1-conor@kernel.org Cc: stable@vger.kernel.org Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'arch/riscv/kernel')
-rw-r--r--arch/riscv/kernel/cpufeature.c6
1 files changed, 5 insertions, 1 deletions
diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
index 694267d1fe81..fd1238df6149 100644
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -9,6 +9,7 @@
#include <linux/bitmap.h>
#include <linux/ctype.h>
#include <linux/libfdt.h>
+#include <linux/memory.h>
#include <linux/module.h>
#include <linux/of.h>
#include <asm/alternative.h>
@@ -316,8 +317,11 @@ void __init_or_module riscv_cpufeature_patch_func(struct alt_entry *begin,
}
tmp = (1U << alt->errata_id);
- if (cpu_req_feature & tmp)
+ if (cpu_req_feature & tmp) {
+ mutex_lock(&text_mutex);
patch_text_nosync(alt->old_ptr, alt->alt_ptr, alt->alt_len);
+ mutex_unlock(&text_mutex);
+ }
}
}
#endif