From: Samuel Holland Date: Tue, 12 Mar 2024 19:56:38 +0000 (-0700) Subject: riscv: Do not save the scratch CSR during suspend X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=fa7d7339016ab7850258e85d6adfd4c4abca5498;p=linux.git 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 Reviewed-by: Andrew Jones Link: https://lore.kernel.org/r/20240312195641.1830521-1-samuel.holland@sifive.com Signed-off-by: Palmer Dabbelt --- diff --git a/arch/riscv/include/asm/suspend.h b/arch/riscv/include/asm/suspend.h index 4718096fa5e3f..4ffb022b097f4 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 8a327b485b90e..c8cec0cc5833c 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);