[RFC PATCH V3 11/43] rv64ilp32_abi: riscv: Introduce PTR_L and PTR_S

guoren
2025-03-25T12:19:25Z

REG_L and REG_S can't satisfy rv64ilp32 abi requirements, because
BITS_PER_LONG != __riscv_xlen. So we introduce new PTR_L and PTR_S
macro to help head.S and entry.S deal with the pointer data type.

Signed-off-by: Guo Ren (Alibaba DAMO Academy) <guoren@kernel.org>
---
arch/riscv/include/asm/asm.h | 13 +++++++++----
arch/riscv/include/asm/scs.h | 4 ++--
arch/riscv/kernel/entry.S | 32 ++++++++++++++++----------------
arch/riscv/kernel/head.S | 8 ++++----
4 files changed, 31 insertions(+), 26 deletions(-)

diff --git a/arch/riscv/include/asm/asm.h b/arch/riscv/include/asm/asm.h
index 776354895b81..e37d73abbedd 100644
--- a/arch/riscv/include/asm/asm.h
+++ b/arch/riscv/include/asm/asm.h
@@ -38,6 +38,7 @@
#define RISCV_SZPTR "8"
#define RISCV_LGPTR "3"
#endif
+#define __PTR_SEL(a, b) __ASM_STR(a)
#elif __SIZEOF_POINTER__ == 4
#ifdef __ASSEMBLY__
#define RISCV_PTR .word
@@ -48,10 +49,14 @@
#define RISCV_SZPTR "4"
#define RISCV_LGPTR "2"
#endif
+#define __PTR_SEL(a, b) __ASM_STR(b)
#else
#error "Unexpected __SIZEOF_POINTER__"
#endif

+#define PTR_L __PTR_SEL(ld, lw)
+#define PTR_S __PTR_SEL(sd, sw)
+
#if (__SIZEOF_INT__ == 4)
#define RISCV_INT __ASM_STR(.word)
#define RISCV_SZINT __ASM_STR(4)
@@ -83,18 +88,18 @@
.endm

#ifdef CONFIG_SMP
-#ifdef CONFIG_32BIT
+#if BITS_PER_LONG == 32
#define PER_CPU_OFFSET_SHIFT 2
#else
#define PER_CPU_OFFSET_SHIFT 3
#endif

.macro asm_per_cpu dst sym tmp
- REG_L \tmp, TASK_TI_CPU_NUM(tp)
+ PTR_L \tmp, TASK_TI_CPU_NUM(tp)
slli \tmp, \tmp, PER_CPU_OFFSET_SHIFT
la \dst, __per_cpu_offset
add \dst, \dst, \tmp
- REG_L \tmp, 0(\dst)
+ PTR_L \tmp, 0(\dst)
la \dst, \sym
add \dst, \dst, \tmp
.endm
@@ -106,7 +111,7 @@

.macro load_per_cpu dst ptr tmp
asm_per_cpu \dst \ptr \tmp
- REG_L \dst, 0(\dst)
+ PTR_L \dst, 0(\dst)
.endm

#ifdef CONFIG_SHADOW_CALL_STACK
diff --git a/arch/riscv/include/asm/scs.h b/arch/riscv/include/asm/scs.h
index 0e45db78b24b..30929afb4e1a 100644
--- a/arch/riscv/include/asm/scs.h
+++ b/arch/riscv/include/asm/scs.h
@@ -20,7 +20,7 @@

/* Load task_scs_sp(current) to gp. */
.macro scs_load_current
- REG_L gp, TASK_TI_SCS_SP(tp)
+ PTR_L gp, TASK_TI_SCS_SP(tp)
.endm

/* Load task_scs_sp(current) to gp, but only if tp has changed. */
@@ -32,7 +32,7 @@

/* Save gp to task_scs_sp(current). */
.macro scs_save_current
- REG_S gp, TASK_TI_SCS_SP(tp)
+ PTR_S gp, TASK_TI_SCS_SP(tp)
.endm

#else /* CONFIG_SHADOW_CALL_STACK */
diff --git a/arch/riscv/kernel/entry.S b/arch/riscv/kernel/entry.S
index 33a5a9f2a0d4..2cf36e3ab6b9 100644
--- a/arch/riscv/kernel/entry.S
+++ b/arch/riscv/kernel/entry.S
@@ -117,19 +117,19 @@ SYM_CODE_START(handle_exception)
new_vmalloc_check
#endif

- REG_S sp, TASK_TI_KERNEL_SP(tp)
+ PTR_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)
+ PTR_L sp, TASK_TI_KERNEL_SP(tp)
#endif

.Lsave_context:
- REG_S sp, TASK_TI_USER_SP(tp)
- REG_L sp, TASK_TI_KERNEL_SP(tp)
+ PTR_S sp, TASK_TI_USER_SP(tp)
+ PTR_L sp, TASK_TI_KERNEL_SP(tp)
addi sp, sp, -(PT_SIZE_ON_STACK)
REG_S x1, PT_RA(sp)
REG_S x3, PT_GP(sp)
@@ -145,7 +145,7 @@ SYM_CODE_START(handle_exception)
*/
li t0, SR_SUM | SR_FS_VS

- REG_L s0, TASK_TI_USER_SP(tp)
+ PTR_L s0, TASK_TI_USER_SP(tp)
csrrc s1, CSR_STATUS, t0
csrr s2, CSR_EPC
csrr s3, CSR_TVAL
@@ -193,7 +193,7 @@ SYM_CODE_START(handle_exception)
add t0, t1, t0
/* Check if exception code lies within bounds */
bgeu t0, t2, 3f
- REG_L t1, 0(t0)
+ PTR_L t1, 0(t0)
2: jalr t1
j ret_from_exception
3:
@@ -226,7 +226,7 @@ SYM_CODE_START_NOALIGN(ret_from_exception)

/* Save unwound kernel stack pointer in thread_info */
addi s0, sp, PT_SIZE_ON_STACK
- REG_S s0, TASK_TI_KERNEL_SP(tp)
+ PTR_S s0, TASK_TI_KERNEL_SP(tp)

/* Save the kernel shadow call stack pointer */
scs_save_current
@@ -301,7 +301,7 @@ SYM_CODE_START_LOCAL(handle_kernel_stack_overflow)
REG_S x5, PT_T0(sp)
save_from_x6_to_x31

- REG_L s0, TASK_TI_KERNEL_SP(tp)
+ PTR_L s0, TASK_TI_KERNEL_SP(tp)
csrr s1, CSR_STATUS
csrr s2, CSR_EPC
csrr s3, CSR_TVAL
@@ -341,8 +341,8 @@ SYM_CODE_END(ret_from_fork)
SYM_FUNC_START(call_on_irq_stack)
/* Create a frame record to save ra and s0 (fp) */
addi sp, sp, -STACKFRAME_SIZE_ON_STACK
- REG_S ra, STACKFRAME_RA(sp)
- REG_S s0, STACKFRAME_FP(sp)
+ PTR_S ra, STACKFRAME_RA(sp)
+ PTR_S s0, STACKFRAME_FP(sp)
addi s0, sp, STACKFRAME_SIZE_ON_STACK

/* Switch to the per-CPU shadow call stack */
@@ -360,8 +360,8 @@ SYM_FUNC_START(call_on_irq_stack)

/* Switch back to the thread stack and restore ra and s0 */
addi sp, s0, -STACKFRAME_SIZE_ON_STACK
- REG_L ra, STACKFRAME_RA(sp)
- REG_L s0, STACKFRAME_FP(sp)
+ PTR_L ra, STACKFRAME_RA(sp)
+ PTR_L s0, STACKFRAME_FP(sp)
addi sp, sp, STACKFRAME_SIZE_ON_STACK

ret
@@ -383,8 +383,8 @@ SYM_FUNC_START(__switch_to)
li a4, TASK_THREAD_RA
add a3, a0, a4
add a4, a1, a4
- REG_S ra, TASK_THREAD_RA_RA(a3)
- REG_S sp, TASK_THREAD_SP_RA(a3)
+ PTR_S ra, TASK_THREAD_RA_RA(a3)
+ PTR_S sp, TASK_THREAD_SP_RA(a3)
REG_S s0, TASK_THREAD_S0_RA(a3)
REG_S s1, TASK_THREAD_S1_RA(a3)
REG_S s2, TASK_THREAD_S2_RA(a3)
@@ -400,8 +400,8 @@ SYM_FUNC_START(__switch_to)
/* Save the kernel shadow call stack pointer */
scs_save_current
/* Restore context from next->thread */
- REG_L ra, TASK_THREAD_RA_RA(a4)
- REG_L sp, TASK_THREAD_SP_RA(a4)
+ PTR_L ra, TASK_THREAD_RA_RA(a4)
+ PTR_L sp, TASK_THREAD_SP_RA(a4)
REG_L s0, TASK_THREAD_S0_RA(a4)
REG_L s1, TASK_THREAD_S1_RA(a4)
REG_L s2, TASK_THREAD_S2_RA(a4)
diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S
index 356d5397b2a2..e55a92be12b1 100644
--- a/arch/riscv/kernel/head.S
+++ b/arch/riscv/kernel/head.S
@@ -42,7 +42,7 @@ SYM_CODE_START(_start)
/* Image load offset (0MB) from start of RAM for M-mode */
.dword 0
#else
-#if __riscv_xlen == 64
+#ifdef CONFIG_64BIT
/* Image load offset(2MB) from start of RAM */
.dword 0x200000
#else
@@ -75,7 +75,7 @@ relocate_enable_mmu:
/* Relocate return address */
la a1, kernel_map
XIP_FIXUP_OFFSET a1
- REG_L a1, KERNEL_MAP_VIRT_ADDR(a1)
+ PTR_L a1, KERNEL_MAP_VIRT_ADDR(a1)
la a2, _start
sub a1, a1, a2
add ra, ra, a1
@@ -349,8 +349,8 @@ SYM_CODE_START(_start_kernel)
*/
.Lwait_for_cpu_up:
/* FIXME: We should WFI to save some energy here. */
- REG_L sp, (a1)
- REG_L tp, (a2)
+ PTR_L sp, (a1)
+ PTR_L tp, (a2)
beqz sp, .Lwait_for_cpu_up
beqz tp, .Lwait_for_cpu_up
fence
--
2.40.1