[PATCH 6.7 108/162] riscv: Save/restore envcfg CSR during CPU suspend

Greg Kroah-Hartman
2024-03-04T21:30:37Z

From: Samuel Holland <samuel.holland@sifive.com>

commit 05ab803d1ad8ac505ade77c6bd3f86b1b4ea0dc4 upstream.

The value of the [ms]envcfg CSR is lost when entering a nonretentive
idle state, so the CSR must be rewritten when resuming the CPU.

Cc: <stable@vger.kernel.org> # v6.7+
Fixes: 43c16d51a19b ("RISC-V: Enable cbo.zero in usermode")
Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Link: https://lore.kernel.org/r/20240228065559.3434837-4-samuel.holland@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/riscv/include/asm/suspend.h | 1 +
arch/riscv/kernel/suspend.c | 4 ++++
2 files changed, 5 insertions(+)

--- a/arch/riscv/include/asm/suspend.h
+++ b/arch/riscv/include/asm/suspend.h
@@ -14,6 +14,7 @@ struct suspend_context {
struct pt_regs regs;
/* Saved and restored by high-level functions */
unsigned long scratch;
+ unsigned long envcfg;
unsigned long tvec;
unsigned long ie;
#ifdef CONFIG_MMU
--- a/arch/riscv/kernel/suspend.c
+++ b/arch/riscv/kernel/suspend.c
@@ -11,6 +11,8 @@
void suspend_save_csrs(struct suspend_context *context)
{
context->scratch = csr_read(CSR_SCRATCH);
+ if (riscv_cpu_has_extension_unlikely(smp_processor_id(), RISCV_ISA_EXT_XLINUXENVCFG))
+ context->envcfg = csr_read(CSR_ENVCFG);
context->tvec = csr_read(CSR_TVEC);
context->ie = csr_read(CSR_IE);

@@ -32,6 +34,8 @@ void suspend_save_csrs(struct suspend_co
void suspend_restore_csrs(struct suspend_context *context)
{
csr_write(CSR_SCRATCH, context->scratch);
+ if (riscv_cpu_has_extension_unlikely(smp_processor_id(), RISCV_ISA_EXT_XLINUXENVCFG))
+ csr_write(CSR_ENVCFG, context->envcfg);
csr_write(CSR_TVEC, context->tvec);
csr_write(CSR_IE, context->ie);