linux-kernel - [PATCH 4/4] riscv: entry: consolidate general regs saving into save

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Date:   Mon, 26 Sep 2022 01:53:56 +0800
From:   Jisheng Zhang <jszhang@...nel.org>
To:     Paul Walmsley <paul.walmsley@...ive.com>,
        Palmer Dabbelt <palmer@...belt.com>,
        Albert Ou <aou@...s.berkeley.edu>, Guo Ren <guoren@...nel.org>,
        Nathan Chancellor <nathan@...nel.org>,
        Nick Desaulniers <ndesaulniers@...gle.com>
Cc:     linux-riscv@...ts.infradead.org, linux-kernel@...r.kernel.org,
        llvm@...ts.linux.dev
Subject: [PATCH 4/4] riscv: entry: consolidate general regs saving into save_gp

Consolidate the saving GPs(except sp and tp into save_gp macro.
No functional change.

Signed-off-by: Jisheng Zhang <jszhang@...nel.org>
---
 arch/riscv/kernel/entry.S | 85 ++++++++++++++-------------------------
 1 file changed, 31 insertions(+), 54 deletions(-)

diff --git a/arch/riscv/kernel/entry.S b/arch/riscv/kernel/entry.S
index 442d93beffcf..04e11d257ad6 100644
--- a/arch/riscv/kernel/entry.S
+++ b/arch/riscv/kernel/entry.S
@@ -14,31 +14,8 @@
 #include <asm/asm-offsets.h>
 #include <asm/errata_list.h>
 
-ENTRY(handle_exception)
-	/*
-	 * If coming from userspace, preserve the user thread pointer and load
-	 * the kernel thread pointer.  If we came from the kernel, the scratch
-	 * register will contain 0, and we should continue on the current TP.
-	 */
-	csrrw tp, CSR_SCRATCH, tp
-	bnez tp, _save_context
-
-_restore_kernel_tpsp:
-	csrr tp, CSR_SCRATCH
-	REG_S sp, TASK_TI_KERNEL_SP(tp)
-
-#ifdef CONFIG_VMAP_STACK
-	addi sp, sp, -(PT_SIZE_ON_STACK)
-	srli sp, sp, THREAD_SHIFT
-	andi sp, sp, 0x1
-	bnez sp, handle_kernel_stack_overflow
-	REG_L sp, TASK_TI_KERNEL_SP(tp)
-#endif
-
-_save_context:
-	REG_S sp, TASK_TI_USER_SP(tp)
-	REG_L sp, TASK_TI_KERNEL_SP(tp)
-	addi sp, sp, -(PT_SIZE_ON_STACK)
+	/* save all GPs except sp and tp */
+	.macro save_gp
 	REG_S x1,  PT_RA(sp)
 	REG_S x3,  PT_GP(sp)
 	REG_S x5,  PT_T0(sp)
@@ -68,6 +45,34 @@ _save_context:
 	REG_S x29, PT_T4(sp)
 	REG_S x30, PT_T5(sp)
 	REG_S x31, PT_T6(sp)
+	.endm
+
+ENTRY(handle_exception)
+	/*
+	 * If coming from userspace, preserve the user thread pointer and load
+	 * the kernel thread pointer.  If we came from the kernel, the scratch
+	 * register will contain 0, and we should continue on the current TP.
+	 */
+	csrrw tp, CSR_SCRATCH, tp
+	bnez tp, _save_context
+
+_restore_kernel_tpsp:
+	csrr tp, CSR_SCRATCH
+	REG_S sp, TASK_TI_KERNEL_SP(tp)
+
+#ifdef CONFIG_VMAP_STACK
+	addi sp, sp, -(PT_SIZE_ON_STACK)
+	srli sp, sp, THREAD_SHIFT
+	andi sp, sp, 0x1
+	bnez sp, handle_kernel_stack_overflow
+	REG_L sp, TASK_TI_KERNEL_SP(tp)
+#endif
+
+_save_context:
+	REG_S sp, TASK_TI_USER_SP(tp)
+	REG_L sp, TASK_TI_KERNEL_SP(tp)
+	addi sp, sp, -(PT_SIZE_ON_STACK)
+	save_gp
 
 	/*
 	 * Disable user-mode memory access as it should only be set in the
@@ -234,35 +239,7 @@ ENTRY(handle_kernel_stack_overflow)
 	addi sp, sp, -(PT_SIZE_ON_STACK)
 
 	//save context to overflow stack
-	REG_S x1,  PT_RA(sp)
-	REG_S x3,  PT_GP(sp)
-	REG_S x5,  PT_T0(sp)
-	REG_S x6,  PT_T1(sp)
-	REG_S x7,  PT_T2(sp)
-	REG_S x8,  PT_S0(sp)
-	REG_S x9,  PT_S1(sp)
-	REG_S x10, PT_A0(sp)
-	REG_S x11, PT_A1(sp)
-	REG_S x12, PT_A2(sp)
-	REG_S x13, PT_A3(sp)
-	REG_S x14, PT_A4(sp)
-	REG_S x15, PT_A5(sp)
-	REG_S x16, PT_A6(sp)
-	REG_S x17, PT_A7(sp)
-	REG_S x18, PT_S2(sp)
-	REG_S x19, PT_S3(sp)
-	REG_S x20, PT_S4(sp)
-	REG_S x21, PT_S5(sp)
-	REG_S x22, PT_S6(sp)
-	REG_S x23, PT_S7(sp)
-	REG_S x24, PT_S8(sp)
-	REG_S x25, PT_S9(sp)
-	REG_S x26, PT_S10(sp)
-	REG_S x27, PT_S11(sp)
-	REG_S x28, PT_T3(sp)
-	REG_S x29, PT_T4(sp)
-	REG_S x30, PT_T5(sp)
-	REG_S x31, PT_T6(sp)
+	save_gp
 
 	REG_L s0, TASK_TI_KERNEL_SP(tp)
 	csrr s1, CSR_STATUS
-- 
2.34.1