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| author | Samuel Holland <samuel.holland@sifive.com> | 2024-03-12 22:56:38 +0300 |
|---|---|---|
| committer | Palmer Dabbelt <palmer@rivosinc.com> | 2024-04-29 00:50:36 +0300 |
| commit | fa7d7339016ab7850258e85d6adfd4c4abca5498 (patch) | |
| tree | 9d3fa584dbbcfc361df629bffeaffee04969e2f4 /arch/riscv | |
| parent | d4b500cceb0e09ae22722d41454df6012848062b (diff) | |
| download | linux-fa7d7339016ab7850258e85d6adfd4c4abca5498.tar.xz | |
riscv: Do not save the scratch CSR during suspend
While the processor is executing kernel code, the value of the scratch
CSR is always zero, so there is no need to save the value. Continue to
write the CSR during the resume flow, so we do not rely on firmware to
initialize it.
Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Link: https://lore.kernel.org/r/20240312195641.1830521-1-samuel.holland@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Diffstat (limited to 'arch/riscv')
| -rw-r--r-- | arch/riscv/include/asm/suspend.h | 1 | ||||
| -rw-r--r-- | arch/riscv/kernel/suspend.c | 3 |
2 files changed, 1 insertions, 3 deletions
diff --git a/arch/riscv/include/asm/suspend.h b/arch/riscv/include/asm/suspend.h index 4718096fa5e3..4ffb022b097f 100644 --- a/arch/riscv/include/asm/suspend.h +++ b/arch/riscv/include/asm/suspend.h @@ -13,7 +13,6 @@ struct suspend_context { /* Saved and restored by low-level functions */ struct pt_regs regs; /* Saved and restored by high-level functions */ - unsigned long scratch; unsigned long envcfg; unsigned long tvec; unsigned long ie; diff --git a/arch/riscv/kernel/suspend.c b/arch/riscv/kernel/suspend.c index 8a327b485b90..c8cec0cc5833 100644 --- a/arch/riscv/kernel/suspend.c +++ b/arch/riscv/kernel/suspend.c @@ -14,7 +14,6 @@ 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); @@ -37,7 +36,7 @@ void suspend_save_csrs(struct suspend_context *context) void suspend_restore_csrs(struct suspend_context *context) { - csr_write(CSR_SCRATCH, context->scratch); + csr_write(CSR_SCRATCH, 0); 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); |