The IPI code could have race conditions in several places. * Several harts could race on the value of gd->arch->clint/plic * Non-boot harts could race with the main hart on the DM subsystem In addition, if an IPI was pending when U-Boot started, it would cause the IPI handler to jump to address 0.
To address these problems, a new function riscv_init_ipi is introduced. It is called once during arch_cpu_init_dm. Before this point, no riscv_*_ipi functions may be called. Access is synchronized by gd->arch->ipi_ready.
Signed-off-by: Sean Anderson seanga2@gmail.com ---
Changes in v6: - Fix some formatting - Clear IPIs before enabling interrupts instead of using a ipi_ready flag - Only print messages on error in smp code
Changes in v5: - New
arch/riscv/cpu/cpu.c | 6 ++++ arch/riscv/cpu/start.S | 2 ++ arch/riscv/include/asm/smp.h | 43 +++++++++++++++++++++++++++ arch/riscv/lib/andes_plic.c | 34 ++++++++------------- arch/riscv/lib/sbi_ipi.c | 5 ++++ arch/riscv/lib/sifive_clint.c | 33 +++++++-------------- arch/riscv/lib/smp.c | 56 ++++++++--------------------------- 7 files changed, 92 insertions(+), 87 deletions(-)
diff --git a/arch/riscv/cpu/cpu.c b/arch/riscv/cpu/cpu.c index e457f6acbf..f851374255 100644 --- a/arch/riscv/cpu/cpu.c +++ b/arch/riscv/cpu/cpu.c @@ -96,6 +96,12 @@ int arch_cpu_init_dm(void) csr_write(CSR_SATP, 0); }
+#ifdef CONFIG_SMP + ret = riscv_init_ipi(); + if (ret) + return ret; +#endif + return 0; }
diff --git a/arch/riscv/cpu/start.S b/arch/riscv/cpu/start.S index 6b3ff99c38..e8740c8568 100644 --- a/arch/riscv/cpu/start.S +++ b/arch/riscv/cpu/start.S @@ -67,6 +67,8 @@ _start: #else li t0, SIE_SSIE #endif + /* Clear any pending IPIs */ + csrc MODE_PREFIX(ip), t0 csrs MODE_PREFIX(ie), t0 #endif
diff --git a/arch/riscv/include/asm/smp.h b/arch/riscv/include/asm/smp.h index 74de92ed13..1b428856b2 100644 --- a/arch/riscv/include/asm/smp.h +++ b/arch/riscv/include/asm/smp.h @@ -51,4 +51,47 @@ void handle_ipi(ulong hart); */ int smp_call_function(ulong addr, ulong arg0, ulong arg1, int wait);
+/** + * riscv_init_ipi() - Initialize inter-process interrupt (IPI) driver + * + * Platform code must provide this function. This function is called once after + * the cpu driver is initialized. No other riscv_*_ipi() calls will be made + * before this function is called. + * + * @return 0 if OK, -ve on error + */ +int riscv_init_ipi(void); + +/** + * riscv_send_ipi() - Send inter-processor interrupt (IPI) + * + * Platform code must provide this function. + * + * @hart: Hart ID of receiving hart + * @return 0 if OK, -ve on error + */ +int riscv_send_ipi(int hart); + +/** + * riscv_clear_ipi() - Clear inter-processor interrupt (IPI) + * + * Platform code must provide this function. + * + * @hart: Hart ID of hart to be cleared + * @return 0 if OK, -ve on error + */ +int riscv_clear_ipi(int hart); + +/** + * riscv_get_ipi() - Get status of inter-processor interrupt (IPI) + * + * Platform code must provide this function. + * + * @hart: Hart ID of hart to be checked + * @pending: Pointer to variable with result of the check, + * 1 if IPI is pending, 0 otherwise + * @return 0 if OK, -ve on error + */ +int riscv_get_ipi(int hart, int *pending); + #endif diff --git a/arch/riscv/lib/andes_plic.c b/arch/riscv/lib/andes_plic.c index 20529ab3eb..8484f76386 100644 --- a/arch/riscv/lib/andes_plic.c +++ b/arch/riscv/lib/andes_plic.c @@ -30,20 +30,6 @@ #define SEND_IPI_TO_HART(hart) (0x80 >> (hart))
DECLARE_GLOBAL_DATA_PTR; -static int init_plic(void); - -#define PLIC_BASE_GET(void) \ - do { \ - long *ret; \ - \ - if (!gd->arch.plic) { \ - ret = syscon_get_first_range(RISCV_SYSCON_PLIC); \ - if (IS_ERR(ret)) \ - return PTR_ERR(ret); \ - gd->arch.plic = ret; \ - init_plic(); \ - } \ - } while (0)
static int enable_ipi(int hart) { @@ -93,13 +79,21 @@ static int init_plic(void) return -ENODEV; }
+int riscv_init_ipi(void) +{ + int ret = syscon_get_first_range(RISCV_SYSCON_PLIC); + + if (IS_ERR(ret)) + return PTR_ERR(ret); + gd->arch.plic = ret; + + return init_plic(); +} + int riscv_send_ipi(int hart) { - unsigned int ipi; + unsigned int ipi = (SEND_IPI_TO_HART(hart) << (8 * gd->arch.boot_hart));
- PLIC_BASE_GET(); - - ipi = (SEND_IPI_TO_HART(hart) << (8 * gd->arch.boot_hart)); writel(ipi, (void __iomem *)PENDING_REG(gd->arch.plic, gd->arch.boot_hart));
@@ -110,8 +104,6 @@ int riscv_clear_ipi(int hart) { u32 source_id;
- PLIC_BASE_GET(); - source_id = readl((void __iomem *)CLAIM_REG(gd->arch.plic, hart)); writel(source_id, (void __iomem *)CLAIM_REG(gd->arch.plic, hart));
@@ -120,8 +112,6 @@ int riscv_clear_ipi(int hart)
int riscv_get_ipi(int hart, int *pending) { - PLIC_BASE_GET(); - *pending = readl((void __iomem *)PENDING_REG(gd->arch.plic, gd->arch.boot_hart)); *pending = !!(*pending & SEND_IPI_TO_HART(hart)); diff --git a/arch/riscv/lib/sbi_ipi.c b/arch/riscv/lib/sbi_ipi.c index 9a698ce74e..310d1bd2a4 100644 --- a/arch/riscv/lib/sbi_ipi.c +++ b/arch/riscv/lib/sbi_ipi.c @@ -7,6 +7,11 @@ #include <common.h> #include <asm/sbi.h>
+int riscv_init_ipi(void) +{ + return 0; +} + int riscv_send_ipi(int hart) { ulong mask; diff --git a/arch/riscv/lib/sifive_clint.c b/arch/riscv/lib/sifive_clint.c index 5e0d25720b..78fc6c868d 100644 --- a/arch/riscv/lib/sifive_clint.c +++ b/arch/riscv/lib/sifive_clint.c @@ -24,22 +24,8 @@
DECLARE_GLOBAL_DATA_PTR;
-#define CLINT_BASE_GET(void) \ - do { \ - long *ret; \ - \ - if (!gd->arch.clint) { \ - ret = syscon_get_first_range(RISCV_SYSCON_CLINT); \ - if (IS_ERR(ret)) \ - return PTR_ERR(ret); \ - gd->arch.clint = ret; \ - } \ - } while (0) - int riscv_get_time(u64 *time) { - CLINT_BASE_GET(); - *time = readq((void __iomem *)MTIME_REG(gd->arch.clint));
return 0; @@ -47,17 +33,24 @@ int riscv_get_time(u64 *time)
int riscv_set_timecmp(int hart, u64 cmp) { - CLINT_BASE_GET(); - writeq(cmp, (void __iomem *)MTIMECMP_REG(gd->arch.clint, hart));
return 0; }
+int riscv_init_ipi(void) +{ + long *ret = syscon_get_first_range(RISCV_SYSCON_CLINT); + + if (IS_ERR(ret)) + return PTR_ERR(ret); + gd->arch.clint = ret; + + return 0; +} + int riscv_send_ipi(int hart) { - CLINT_BASE_GET(); - writel(1, (void __iomem *)MSIP_REG(gd->arch.clint, hart));
return 0; @@ -65,8 +58,6 @@ int riscv_send_ipi(int hart)
int riscv_clear_ipi(int hart) { - CLINT_BASE_GET(); - writel(0, (void __iomem *)MSIP_REG(gd->arch.clint, hart));
return 0; @@ -74,8 +65,6 @@ int riscv_clear_ipi(int hart)
int riscv_get_ipi(int hart, int *pending) { - CLINT_BASE_GET(); - *pending = readl((void __iomem *)MSIP_REG(gd->arch.clint, hart));
return 0; diff --git a/arch/riscv/lib/smp.c b/arch/riscv/lib/smp.c index 17adb35730..fe992eb00f 100644 --- a/arch/riscv/lib/smp.c +++ b/arch/riscv/lib/smp.c @@ -12,38 +12,6 @@
DECLARE_GLOBAL_DATA_PTR;
-/** - * riscv_send_ipi() - Send inter-processor interrupt (IPI) - * - * Platform code must provide this function. - * - * @hart: Hart ID of receiving hart - * @return 0 if OK, -ve on error - */ -extern int riscv_send_ipi(int hart); - -/** - * riscv_clear_ipi() - Clear inter-processor interrupt (IPI) - * - * Platform code must provide this function. - * - * @hart: Hart ID of hart to be cleared - * @return 0 if OK, -ve on error - */ -extern int riscv_clear_ipi(int hart); - -/** - * riscv_get_ipi() - Get status of inter-processor interrupt (IPI) - * - * Platform code must provide this function. - * - * @hart: Hart ID of hart to be checked - * @pending: Pointer to variable with result of the check, - * 1 if IPI is pending, 0 otherwise - * @return 0 if OK, -ve on error - */ -extern int riscv_get_ipi(int hart, int *pending); - static int send_ipi_many(struct ipi_data *ipi, int wait) { ofnode node, cpus; @@ -114,7 +82,6 @@ void handle_ipi(ulong hart) return;
__smp_mb(); - smp_function = (void (*)(ulong, ulong, ulong))gd->arch.ipi[hart].addr; invalidate_icache_all();
@@ -124,7 +91,13 @@ void handle_ipi(ulong hart) */ ret = riscv_clear_ipi(hart); if (ret) { - pr_err("Cannot clear IPI of hart %ld\n", hart); + pr_err("Cannot clear IPI of hart %ld (error %d)\n", hart, ret); + return; + } + + /* Sanity check */ + if (!smp_function) { + pr_err("smp_function is NULL on hart %ld\n", hart); return; }
@@ -133,14 +106,11 @@ void handle_ipi(ulong hart)
int smp_call_function(ulong addr, ulong arg0, ulong arg1, int wait) { - int ret = 0; - struct ipi_data ipi; + struct ipi_data ipi = { + .addr = addr, + .arg0 = arg0, + .arg1 = arg1, + };
- ipi.addr = addr; - ipi.arg0 = arg0; - ipi.arg1 = arg1; - - ret = send_ipi_many(&ipi, wait); - - return ret; + return send_ipi_many(&ipi, wait); }