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authorAnup Patel <Anup.Patel@wdc.com>2019-04-25 08:38:41 +0000
committerPalmer Dabbelt <palmer@sifive.com>2019-05-16 20:42:11 -0700
commita3182c91ef4e7dda90ff080a4132efd3ecb8786a (patch)
tree5309b2480f3c6bb9e6df4d7921c7a71ce18dcc4d /arch/riscv/kernel/entry.S
parent6dcaf00487ca10d87e53fc8decb2e30f113c955d (diff)
downloadlinux-a3182c91ef4e7dda90ff080a4132efd3ecb8786a.tar.bz2
RISC-V: Access CSRs using CSR numbers
We should prefer accessing CSRs using their CSR numbers because: 1. It compiles fine with older toolchains. 2. We can use latest CSR names in #define macro names of CSR numbers as-per RISC-V spec. 3. We can access newly added CSRs even if toolchain does not recognize newly addes CSRs by name. Signed-off-by: Anup Patel <anup.patel@wdc.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
Diffstat (limited to 'arch/riscv/kernel/entry.S')
-rw-r--r--arch/riscv/kernel/entry.S22
1 files changed, 11 insertions, 11 deletions
diff --git a/arch/riscv/kernel/entry.S b/arch/riscv/kernel/entry.S
index fd9b57c8b4ce..1c1ecc238cfa 100644
--- a/arch/riscv/kernel/entry.S
+++ b/arch/riscv/kernel/entry.S
@@ -37,11 +37,11 @@
* the kernel thread pointer. If we came from the kernel, sscratch
* will contain 0, and we should continue on the current TP.
*/
- csrrw tp, sscratch, tp
+ csrrw tp, CSR_SSCRATCH, tp
bnez tp, _save_context
_restore_kernel_tpsp:
- csrr tp, sscratch
+ csrr tp, CSR_SSCRATCH
REG_S sp, TASK_TI_KERNEL_SP(tp)
_save_context:
REG_S sp, TASK_TI_USER_SP(tp)
@@ -87,11 +87,11 @@ _save_context:
li t0, SR_SUM | SR_FS
REG_L s0, TASK_TI_USER_SP(tp)
- csrrc s1, sstatus, t0
- csrr s2, sepc
- csrr s3, sbadaddr
- csrr s4, scause
- csrr s5, sscratch
+ csrrc s1, CSR_SSTATUS, t0
+ csrr s2, CSR_SEPC
+ csrr s3, CSR_STVAL
+ csrr s4, CSR_SCAUSE
+ csrr s5, CSR_SSCRATCH
REG_S s0, PT_SP(sp)
REG_S s1, PT_SSTATUS(sp)
REG_S s2, PT_SEPC(sp)
@@ -107,8 +107,8 @@ _save_context:
.macro RESTORE_ALL
REG_L a0, PT_SSTATUS(sp)
REG_L a2, PT_SEPC(sp)
- csrw sstatus, a0
- csrw sepc, a2
+ csrw CSR_SSTATUS, a0
+ csrw CSR_SEPC, a2
REG_L x1, PT_RA(sp)
REG_L x3, PT_GP(sp)
@@ -155,7 +155,7 @@ ENTRY(handle_exception)
* Set sscratch register to 0, so that if a recursive exception
* occurs, the exception vector knows it came from the kernel
*/
- csrw sscratch, x0
+ csrw CSR_SSCRATCH, x0
/* Load the global pointer */
.option push
@@ -248,7 +248,7 @@ resume_userspace:
* Save TP into sscratch, so we can find the kernel data structures
* again.
*/
- csrw sscratch, tp
+ csrw CSR_SSCRATCH, tp
restore_all:
RESTORE_ALL