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@vger.kernel.org Fixes: 43c16d51a19b ("RISC-V: Enable cbo.zero in usermode") Reviewed-by: Andrew Jones ajones@ventanamicro.com Signed-off-by: Samuel Holland samuel.holland@sifive.com
(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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