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RISC-V: Access CSRs using CSR numbers

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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>
This commit is contained in:
Anup Patel 2019-04-25 08:38:41 +00:00 committed by Palmer Dabbelt
parent 6dcaf00487
commit a3182c91ef
No known key found for this signature in database
GPG Key ID: EF4CA1502CCBAB41
9 changed files with 57 additions and 48 deletions
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32
arch/riscv/include/asm/csr.h
View File

@ -14,6 +14,7 @@
#ifndef _ASM_RISCV_CSR_H
#define _ASM_RISCV_CSR_H
#include <asm/asm.h>
#include <linux/const.h>
/* Status register flags */
@ -79,12 +80,29 @@
#define SIE_STIE (_AC(0x1, UL) << IRQ_S_TIMER)
#define SIE_SEIE (_AC(0x1, UL) << IRQ_S_EXT)
#define CSR_CYCLE 0xc00
#define CSR_TIME 0xc01
#define CSR_INSTRET 0xc02
#define CSR_SSTATUS 0x100
#define CSR_SIE 0x104
#define CSR_STVEC 0x105
#define CSR_SCOUNTEREN 0x106
#define CSR_SSCRATCH 0x140
#define CSR_SEPC 0x141
#define CSR_SCAUSE 0x142
#define CSR_STVAL 0x143
#define CSR_SIP 0x144
#define CSR_SATP 0x180
#define CSR_CYCLEH 0xc80
#define CSR_TIMEH 0xc81
#define CSR_INSTRETH 0xc82
#ifndef __ASSEMBLY__
#define csr_swap(csr, val) \
({ \
unsigned long __v = (unsigned long)(val); \
__asm__ __volatile__ ("csrrw %0, " #csr ", %1" \
__asm__ __volatile__ ("csrrw %0, " __ASM_STR(csr) ", %1"\
: "=r" (__v) : "rK" (__v) \
: "memory"); \
__v; \
@ -93,7 +111,7 @@
#define csr_read(csr) \
({ \
register unsigned long __v; \
__asm__ __volatile__ ("csrr %0, " #csr \
__asm__ __volatile__ ("csrr %0, " __ASM_STR(csr) \
: "=r" (__v) : \
: "memory"); \
__v; \
@ -102,7 +120,7 @@
#define csr_write(csr, val) \
({ \
unsigned long __v = (unsigned long)(val); \
__asm__ __volatile__ ("csrw " #csr ", %0" \
__asm__ __volatile__ ("csrw " __ASM_STR(csr) ", %0" \
: : "rK" (__v) \
: "memory"); \
})
@ -110,7 +128,7 @@
#define csr_read_set(csr, val) \
({ \
unsigned long __v = (unsigned long)(val); \
__asm__ __volatile__ ("csrrs %0, " #csr ", %1" \
__asm__ __volatile__ ("csrrs %0, " __ASM_STR(csr) ", %1"\
: "=r" (__v) : "rK" (__v) \
: "memory"); \
__v; \
@ -119,7 +137,7 @@
#define csr_set(csr, val) \
({ \
unsigned long __v = (unsigned long)(val); \
__asm__ __volatile__ ("csrs " #csr ", %0" \
__asm__ __volatile__ ("csrs " __ASM_STR(csr) ", %0" \
: : "rK" (__v) \
: "memory"); \
})
@ -127,7 +145,7 @@
#define csr_read_clear(csr, val) \
({ \
unsigned long __v = (unsigned long)(val); \
__asm__ __volatile__ ("csrrc %0, " #csr ", %1" \
__asm__ __volatile__ ("csrrc %0, " __ASM_STR(csr) ", %1"\
: "=r" (__v) : "rK" (__v) \
: "memory"); \
__v; \
@ -136,7 +154,7 @@
#define csr_clear(csr, val) \
({ \
unsigned long __v = (unsigned long)(val); \
__asm__ __volatile__ ("csrc " #csr ", %0" \
__asm__ __volatile__ ("csrc " __ASM_STR(csr) ", %0" \
: : "rK" (__v) \
: "memory"); \
})

10
arch/riscv/include/asm/irqflags.h
View File

@ -21,25 +21,25 @@
/* read interrupt enabled status */
static inline unsigned long arch_local_save_flags(void)
{
return csr_read(sstatus);
return csr_read(CSR_SSTATUS);
}
/* unconditionally enable interrupts */
static inline void arch_local_irq_enable(void)
{
csr_set(sstatus, SR_SIE);
csr_set(CSR_SSTATUS, SR_SIE);
}
/* unconditionally disable interrupts */
static inline void arch_local_irq_disable(void)
{
csr_clear(sstatus, SR_SIE);
csr_clear(CSR_SSTATUS, SR_SIE);
}
/* get status and disable interrupts */
static inline unsigned long arch_local_irq_save(void)
{
return csr_read_clear(sstatus, SR_SIE);
return csr_read_clear(CSR_SSTATUS, SR_SIE);
}
/* test flags */
@ -57,7 +57,7 @@ static inline int arch_irqs_disabled(void)
/* set interrupt enabled status */
static inline void arch_local_irq_restore(unsigned long flags)
{
csr_set(sstatus, flags & SR_SIE);
csr_set(CSR_SSTATUS, flags & SR_SIE);
}
#endif /* _ASM_RISCV_IRQFLAGS_H */

7
arch/riscv/include/asm/mmu_context.h
View File

@ -83,12 +83,7 @@ static inline void switch_mm(struct mm_struct *prev,
cpumask_clear_cpu(cpu, mm_cpumask(prev));
cpumask_set_cpu(cpu, mm_cpumask(next));
/*
* Use the old spbtr name instead of using the current satp
* name to support binutils 2.29 which doesn't know about the
* privileged ISA 1.10 yet.
*/
csr_write(sptbr, virt_to_pfn(next->pgd) | SATP_MODE);
csr_write(CSR_SATP, virt_to_pfn(next->pgd) | SATP_MODE);
local_flush_tlb_all();
flush_icache_deferred(next);

22
arch/riscv/kernel/entry.S
View File

@ -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

16
arch/riscv/kernel/head.S
View File

@ -22,9 +22,9 @@
__INIT
ENTRY(_start)
/* Mask and clear all interrupts */
csrw sie, zero
csrw sip, zero
/* Mask all interrupts */
csrw CSR_SIE, zero
csrw CSR_SIP, zero
/* Load the global pointer */
.option push
@ -86,7 +86,7 @@ relocate:
/* Point stvec to virtual address of intruction after satp write */
la a0, 1f
add a0, a0, a1
csrw stvec, a0
csrw CSR_STVEC, a0
/* Compute satp for kernel page tables, but don't load it yet */
la a2, swapper_pg_dir
@ -102,12 +102,12 @@ relocate:
srl a0, a0, PAGE_SHIFT
or a0, a0, a1
sfence.vma
csrw sptbr, a0
csrw CSR_SATP, a0
.align 2
1:
/* Set trap vector to spin forever to help debug */
la a0, .Lsecondary_park
csrw stvec, a0
csrw CSR_STVEC, a0
/* Reload the global pointer */
.option push
@ -116,7 +116,7 @@ relocate:
.option pop
/* Switch to kernel page tables */
csrw sptbr, a2
csrw CSR_SATP, a2
ret
@ -127,7 +127,7 @@ relocate:
/* Set trap vector to spin forever to help debug */
la a3, .Lsecondary_park
csrw stvec, a3
csrw CSR_STVEC, a3
slli a3, a0, LGREG
la a1, __cpu_up_stack_pointer

4
arch/riscv/kernel/perf_event.c
View File

@ -185,10 +185,10 @@ static inline u64 read_counter(int idx)
switch (idx) {
case RISCV_PMU_CYCLE:
val = csr_read(cycle);
val = csr_read(CSR_CYCLE);
break;
case RISCV_PMU_INSTRET:
val = csr_read(instret);
val = csr_read(CSR_INSTRET);
break;
default:
WARN_ON_ONCE(idx < 0 || idx > RISCV_MAX_COUNTERS);

2
arch/riscv/kernel/smp.c
View File

@ -95,7 +95,7 @@ void riscv_software_interrupt(void)
unsigned long *stats = ipi_data[smp_processor_id()].stats;
/* Clear pending IPI */
csr_clear(sip, SIE_SSIE);
csr_clear(CSR_SIP, SIE_SSIE);
while (true) {
unsigned long ops;

6
arch/riscv/kernel/traps.c
View File

@ -159,9 +159,9 @@ void __init trap_init(void)
* Set sup0 scratch register to 0, indicating to exception vector
* that we are presently executing in the kernel
*/
csr_write(sscratch, 0);
csr_write(CSR_SSCRATCH, 0);
/* Set the exception vector address */
csr_write(stvec, &handle_exception);
csr_write(CSR_STVEC, &handle_exception);
/* Enable all interrupts */
csr_write(sie, -1);
csr_write(CSR_SIE, -1);
}

6
arch/riscv/mm/fault.c
View File

@ -239,13 +239,9 @@ asmlinkage void do_page_fault(struct pt_regs *regs)
* Do _not_ use "tsk->active_mm->pgd" here.
* We might be inside an interrupt in the middle
* of a task switch.
*
* Note: Use the old spbtr name instead of using the current
* satp name to support binutils 2.29 which doesn't know about
* the privileged ISA 1.10 yet.
*/
index = pgd_index(addr);
pgd = (pgd_t *)pfn_to_virt(csr_read(sptbr)) + index;
pgd = (pgd_t *)pfn_to_virt(csr_read(CSR_SATP)) + index;
pgd_k = init_mm.pgd + index;
if (!pgd_present(*pgd_k))