diff mbox series

[3/3] RISC-V: Access CSRs using CSR numbers

Message ID 20190413073906.53676-4-anup.patel@wdc.com (mailing list archive)
State New, archived
Headers show
Series Allow accessing CSR using CSR number | expand

Commit Message

Anup Patel April 13, 2019, 7:39 a.m. UTC 
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>
---
 arch/riscv/include/asm/csr.h         | 15 ++++++++-------
 arch/riscv/include/asm/irqflags.h    | 10 +++++-----
 arch/riscv/include/asm/mmu_context.h |  2 +-
 arch/riscv/kernel/entry.S            | 22 +++++++++++-----------
 arch/riscv/kernel/head.S             | 12 ++++++------
 arch/riscv/kernel/perf_event.c       |  4 ++--
 arch/riscv/kernel/smp.c              |  2 +-
 arch/riscv/kernel/traps.c            |  6 +++---
 arch/riscv/mm/fault.c                |  2 +-
 9 files changed, 38 insertions(+), 37 deletions(-)

--
2.17.1

Comments

Christoph Hellwig April 13, 2019, 7:55 a.m. UTC | #1 
On Sat, Apr 13, 2019 at 07:39:44AM +0000, Anup Patel wrote:
> 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.

This looks mostly fine, but also please remove all the comments
regarding using sptbr instead of satp now that they are not true
anymore.
Anup Patel April 13, 2019, 8:15 a.m. UTC | #2 
On Sat, Apr 13, 2019 at 1:25 PM Christoph Hellwig <hch@infradead.org> wrote:
>
> On Sat, Apr 13, 2019 at 07:39:44AM +0000, Anup Patel wrote:
> > 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.
>
> This looks mostly fine, but also please remove all the comments
> regarding using sptbr instead of satp now that they are not true
> anymore.

Sure, will do.

Regards,
Anup
diff mbox series

Patch

diff --git a/arch/riscv/include/asm/csr.h b/arch/riscv/include/asm/csr.h
index 8cf698e39463..6bf5652d3565 100644
--- a/arch/riscv/include/asm/csr.h
+++ b/arch/riscv/include/asm/csr.h
@@ -14,6 +14,7 @@ 
 #ifndef _ASM_RISCV_CSR_H
 #define _ASM_RISCV_CSR_H

+#include <asm/asm.h>
 #include <asm/encoding.h>

 #ifndef __ASSEMBLY__
@@ -21,7 +22,7 @@ 
 #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;							\
@@ -30,7 +31,7 @@ 
 #define csr_read(csr)						\
 ({								\
 	register unsigned long __v;				\
-	__asm__ __volatile__ ("csrr %0, " #csr			\
+	__asm__ __volatile__ ("csrr %0, " __ASM_STR(csr)	\
 			      : "=r" (__v) :			\
 			      : "memory");			\
 	__v;							\
@@ -39,7 +40,7 @@ 
 #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");			\
 })
@@ -47,7 +48,7 @@ 
 #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;							\
@@ -56,7 +57,7 @@ 
 #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");			\
 })
@@ -64,7 +65,7 @@ 
 #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;							\
@@ -73,7 +74,7 @@ 
 #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");			\
 })
diff --git a/arch/riscv/include/asm/irqflags.h b/arch/riscv/include/asm/irqflags.h
index 07a3c6d5706f..1a69b3bcd371 100644
--- a/arch/riscv/include/asm/irqflags.h
+++ b/arch/riscv/include/asm/irqflags.h
@@ -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 */
diff --git a/arch/riscv/include/asm/mmu_context.h b/arch/riscv/include/asm/mmu_context.h
index 336d60ec5698..42094c3f80d6 100644
--- a/arch/riscv/include/asm/mmu_context.h
+++ b/arch/riscv/include/asm/mmu_context.h
@@ -88,7 +88,7 @@  static inline void switch_mm(struct mm_struct *prev,
 		 * 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);
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
diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S
index fe884cd69abd..041492636b45 100644
--- a/arch/riscv/kernel/head.S
+++ b/arch/riscv/kernel/head.S
@@ -23,7 +23,7 @@ 
 __INIT
 ENTRY(_start)
 	/* Mask all interrupts */
-	csrw sie, zero
+	csrw CSR_SIE, zero

 	/* Load the global pointer */
 .option push
@@ -89,7 +89,7 @@  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
@@ -105,12 +105,12 @@  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
@@ -119,7 +119,7 @@  relocate:
 .option pop

 	/* Switch to kernel page tables */
-	csrw sptbr, a2
+	csrw CSR_SATP, a2

 	ret

@@ -130,7 +130,7 @@  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
diff --git a/arch/riscv/kernel/perf_event.c b/arch/riscv/kernel/perf_event.c
index 667ee70defea..91626d9ae5f2 100644
--- a/arch/riscv/kernel/perf_event.c
+++ b/arch/riscv/kernel/perf_event.c
@@ -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);
diff --git a/arch/riscv/kernel/smp.c b/arch/riscv/kernel/smp.c
index 0c41d07ec281..f244c63d29e4 100644
--- a/arch/riscv/kernel/smp.c
+++ b/arch/riscv/kernel/smp.c
@@ -89,7 +89,7 @@  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;
diff --git a/arch/riscv/kernel/traps.c b/arch/riscv/kernel/traps.c
index 24a9333dda2c..1b407a9db3fc 100644
--- a/arch/riscv/kernel/traps.c
+++ b/arch/riscv/kernel/traps.c
@@ -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);
 }
diff --git a/arch/riscv/mm/fault.c b/arch/riscv/mm/fault.c
index 88401d5125bc..bb0461ed7efc 100644
--- a/arch/riscv/mm/fault.c
+++ b/arch/riscv/mm/fault.c
@@ -245,7 +245,7 @@  asmlinkage void do_page_fault(struct pt_regs *regs)
 		 * 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))