Hi Samuel,
On 14/02/2024 10:28, Andrew Jones wrote:
On Wed, Feb 14, 2024 at 01:01:56AM -0800, Samuel Holland wrote:
When the kernel is running in M-mode, the CBZE bit must be set in the
menvcfg CSR, not in senvcfg.
Cc: <stable@xxxxxxxxxxxxxxx>
Fixes: 43c16d51a19b ("RISC-V: Enable cbo.zero in usermode")
Reviewed-by: Andrew Jones <ajones@xxxxxxxxxxxxxxxx>
Signed-off-by: Samuel Holland <samuel.holland@xxxxxxxxxx>
---
(no changes since v1)
arch/riscv/include/asm/csr.h | 2 ++
arch/riscv/kernel/cpufeature.c | 2 +-
2 files changed, 3 insertions(+), 1 deletion(-)
diff --git a/arch/riscv/include/asm/csr.h b/arch/riscv/include/asm/csr.h
index 510014051f5d..2468c55933cd 100644
--- a/arch/riscv/include/asm/csr.h
+++ b/arch/riscv/include/asm/csr.h
@@ -424,6 +424,7 @@
# define CSR_STATUS CSR_MSTATUS
# define CSR_IE CSR_MIE
# define CSR_TVEC CSR_MTVEC
+# define CSR_ENVCFG CSR_MENVCFG
# define CSR_SCRATCH CSR_MSCRATCH
# define CSR_EPC CSR_MEPC
# define CSR_CAUSE CSR_MCAUSE
@@ -448,6 +449,7 @@
# define CSR_STATUS CSR_SSTATUS
# define CSR_IE CSR_SIE
# define CSR_TVEC CSR_STVEC
+# define CSR_ENVCFG CSR_SENVCFG
# define CSR_SCRATCH CSR_SSCRATCH
# define CSR_EPC CSR_SEPC
# define CSR_CAUSE CSR_SCAUSE
diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
index 89920f84d0a3..c5b13f7dd482 100644
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -950,7 +950,7 @@ arch_initcall(check_unaligned_access_all_cpus);
void riscv_user_isa_enable(void)
{
if (riscv_cpu_has_extension_unlikely(smp_processor_id(), RISCV_ISA_EXT_ZICBOZ))
- csr_set(CSR_SENVCFG, ENVCFG_CBZE);
+ csr_set(CSR_ENVCFG, ENVCFG_CBZE);
}
#ifdef CONFIG_RISCV_ALTERNATIVE
--
2.43.0
After our back and forth on how we determine the existence of the *envcfg
CSRs, I wonder if we shouldn't put a comment above this
riscv_user_isa_enable() function capturing the [current] decision.
Something like
/*
* While the [ms]envcfg CSRs weren't defined until priv spec 1.12,
* they're assumed to be present when an extension is present which
* specifies [ms]envcfg bit(s). Hence, we don't do any additional
* priv spec version checks or CSR probes here.
*/
I was about to read the whole discussion in v2 to understand the
v3...thank you Drew :) I think it really makes sense to add this
comment, do you intend to do so Samuel?
Thanks,
Alex
Thanks,
drew
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