summaryrefslogtreecommitdiff
path: root/arch/riscv/kernel/traps_misaligned.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/riscv/kernel/traps_misaligned.c')
-rw-r--r--arch/riscv/kernel/traps_misaligned.c648
1 files changed, 648 insertions, 0 deletions
diff --git a/arch/riscv/kernel/traps_misaligned.c b/arch/riscv/kernel/traps_misaligned.c
new file mode 100644
index 000000000000..2adb7c3e4dd5
--- /dev/null
+++ b/arch/riscv/kernel/traps_misaligned.c
@@ -0,0 +1,648 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2020 Western Digital Corporation or its affiliates.
+ */
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/perf_event.h>
+#include <linux/irq.h>
+#include <linux/stringify.h>
+
+#include <asm/processor.h>
+#include <asm/ptrace.h>
+#include <asm/csr.h>
+#include <asm/entry-common.h>
+#include <asm/hwprobe.h>
+#include <asm/cpufeature.h>
+
+#define INSN_MATCH_LB 0x3
+#define INSN_MASK_LB 0x707f
+#define INSN_MATCH_LH 0x1003
+#define INSN_MASK_LH 0x707f
+#define INSN_MATCH_LW 0x2003
+#define INSN_MASK_LW 0x707f
+#define INSN_MATCH_LD 0x3003
+#define INSN_MASK_LD 0x707f
+#define INSN_MATCH_LBU 0x4003
+#define INSN_MASK_LBU 0x707f
+#define INSN_MATCH_LHU 0x5003
+#define INSN_MASK_LHU 0x707f
+#define INSN_MATCH_LWU 0x6003
+#define INSN_MASK_LWU 0x707f
+#define INSN_MATCH_SB 0x23
+#define INSN_MASK_SB 0x707f
+#define INSN_MATCH_SH 0x1023
+#define INSN_MASK_SH 0x707f
+#define INSN_MATCH_SW 0x2023
+#define INSN_MASK_SW 0x707f
+#define INSN_MATCH_SD 0x3023
+#define INSN_MASK_SD 0x707f
+
+#define INSN_MATCH_FLW 0x2007
+#define INSN_MASK_FLW 0x707f
+#define INSN_MATCH_FLD 0x3007
+#define INSN_MASK_FLD 0x707f
+#define INSN_MATCH_FLQ 0x4007
+#define INSN_MASK_FLQ 0x707f
+#define INSN_MATCH_FSW 0x2027
+#define INSN_MASK_FSW 0x707f
+#define INSN_MATCH_FSD 0x3027
+#define INSN_MASK_FSD 0x707f
+#define INSN_MATCH_FSQ 0x4027
+#define INSN_MASK_FSQ 0x707f
+
+#define INSN_MATCH_C_LD 0x6000
+#define INSN_MASK_C_LD 0xe003
+#define INSN_MATCH_C_SD 0xe000
+#define INSN_MASK_C_SD 0xe003
+#define INSN_MATCH_C_LW 0x4000
+#define INSN_MASK_C_LW 0xe003
+#define INSN_MATCH_C_SW 0xc000
+#define INSN_MASK_C_SW 0xe003
+#define INSN_MATCH_C_LDSP 0x6002
+#define INSN_MASK_C_LDSP 0xe003
+#define INSN_MATCH_C_SDSP 0xe002
+#define INSN_MASK_C_SDSP 0xe003
+#define INSN_MATCH_C_LWSP 0x4002
+#define INSN_MASK_C_LWSP 0xe003
+#define INSN_MATCH_C_SWSP 0xc002
+#define INSN_MASK_C_SWSP 0xe003
+
+#define INSN_MATCH_C_FLD 0x2000
+#define INSN_MASK_C_FLD 0xe003
+#define INSN_MATCH_C_FLW 0x6000
+#define INSN_MASK_C_FLW 0xe003
+#define INSN_MATCH_C_FSD 0xa000
+#define INSN_MASK_C_FSD 0xe003
+#define INSN_MATCH_C_FSW 0xe000
+#define INSN_MASK_C_FSW 0xe003
+#define INSN_MATCH_C_FLDSP 0x2002
+#define INSN_MASK_C_FLDSP 0xe003
+#define INSN_MATCH_C_FSDSP 0xa002
+#define INSN_MASK_C_FSDSP 0xe003
+#define INSN_MATCH_C_FLWSP 0x6002
+#define INSN_MASK_C_FLWSP 0xe003
+#define INSN_MATCH_C_FSWSP 0xe002
+#define INSN_MASK_C_FSWSP 0xe003
+
+#define INSN_LEN(insn) ((((insn) & 0x3) < 0x3) ? 2 : 4)
+
+#if defined(CONFIG_64BIT)
+#define LOG_REGBYTES 3
+#define XLEN 64
+#else
+#define LOG_REGBYTES 2
+#define XLEN 32
+#endif
+#define REGBYTES (1 << LOG_REGBYTES)
+#define XLEN_MINUS_16 ((XLEN) - 16)
+
+#define SH_RD 7
+#define SH_RS1 15
+#define SH_RS2 20
+#define SH_RS2C 2
+
+#define RV_X(x, s, n) (((x) >> (s)) & ((1 << (n)) - 1))
+#define RVC_LW_IMM(x) ((RV_X(x, 6, 1) << 2) | \
+ (RV_X(x, 10, 3) << 3) | \
+ (RV_X(x, 5, 1) << 6))
+#define RVC_LD_IMM(x) ((RV_X(x, 10, 3) << 3) | \
+ (RV_X(x, 5, 2) << 6))
+#define RVC_LWSP_IMM(x) ((RV_X(x, 4, 3) << 2) | \
+ (RV_X(x, 12, 1) << 5) | \
+ (RV_X(x, 2, 2) << 6))
+#define RVC_LDSP_IMM(x) ((RV_X(x, 5, 2) << 3) | \
+ (RV_X(x, 12, 1) << 5) | \
+ (RV_X(x, 2, 3) << 6))
+#define RVC_SWSP_IMM(x) ((RV_X(x, 9, 4) << 2) | \
+ (RV_X(x, 7, 2) << 6))
+#define RVC_SDSP_IMM(x) ((RV_X(x, 10, 3) << 3) | \
+ (RV_X(x, 7, 3) << 6))
+#define RVC_RS1S(insn) (8 + RV_X(insn, SH_RD, 3))
+#define RVC_RS2S(insn) (8 + RV_X(insn, SH_RS2C, 3))
+#define RVC_RS2(insn) RV_X(insn, SH_RS2C, 5)
+
+#define SHIFT_RIGHT(x, y) \
+ ((y) < 0 ? ((x) << -(y)) : ((x) >> (y)))
+
+#define REG_MASK \
+ ((1 << (5 + LOG_REGBYTES)) - (1 << LOG_REGBYTES))
+
+#define REG_OFFSET(insn, pos) \
+ (SHIFT_RIGHT((insn), (pos) - LOG_REGBYTES) & REG_MASK)
+
+#define REG_PTR(insn, pos, regs) \
+ (ulong *)((ulong)(regs) + REG_OFFSET(insn, pos))
+
+#define GET_RM(insn) (((insn) >> 12) & 7)
+
+#define GET_RS1(insn, regs) (*REG_PTR(insn, SH_RS1, regs))
+#define GET_RS2(insn, regs) (*REG_PTR(insn, SH_RS2, regs))
+#define GET_RS1S(insn, regs) (*REG_PTR(RVC_RS1S(insn), 0, regs))
+#define GET_RS2S(insn, regs) (*REG_PTR(RVC_RS2S(insn), 0, regs))
+#define GET_RS2C(insn, regs) (*REG_PTR(insn, SH_RS2C, regs))
+#define GET_SP(regs) (*REG_PTR(2, 0, regs))
+#define SET_RD(insn, regs, val) (*REG_PTR(insn, SH_RD, regs) = (val))
+#define IMM_I(insn) ((s32)(insn) >> 20)
+#define IMM_S(insn) (((s32)(insn) >> 25 << 5) | \
+ (s32)(((insn) >> 7) & 0x1f))
+#define MASK_FUNCT3 0x7000
+
+#define GET_PRECISION(insn) (((insn) >> 25) & 3)
+#define GET_RM(insn) (((insn) >> 12) & 7)
+#define PRECISION_S 0
+#define PRECISION_D 1
+
+#ifdef CONFIG_FPU
+
+#define FP_GET_RD(insn) (insn >> 7 & 0x1F)
+
+extern void put_f32_reg(unsigned long fp_reg, unsigned long value);
+
+static int set_f32_rd(unsigned long insn, struct pt_regs *regs,
+ unsigned long val)
+{
+ unsigned long fp_reg = FP_GET_RD(insn);
+
+ put_f32_reg(fp_reg, val);
+ regs->status |= SR_FS_DIRTY;
+
+ return 0;
+}
+
+extern void put_f64_reg(unsigned long fp_reg, unsigned long value);
+
+static int set_f64_rd(unsigned long insn, struct pt_regs *regs, u64 val)
+{
+ unsigned long fp_reg = FP_GET_RD(insn);
+ unsigned long value;
+
+#if __riscv_xlen == 32
+ value = (unsigned long) &val;
+#else
+ value = val;
+#endif
+ put_f64_reg(fp_reg, value);
+ regs->status |= SR_FS_DIRTY;
+
+ return 0;
+}
+
+#if __riscv_xlen == 32
+extern void get_f64_reg(unsigned long fp_reg, u64 *value);
+
+static u64 get_f64_rs(unsigned long insn, u8 fp_reg_offset,
+ struct pt_regs *regs)
+{
+ unsigned long fp_reg = (insn >> fp_reg_offset) & 0x1F;
+ u64 val;
+
+ get_f64_reg(fp_reg, &val);
+ regs->status |= SR_FS_DIRTY;
+
+ return val;
+}
+#else
+
+extern unsigned long get_f64_reg(unsigned long fp_reg);
+
+static unsigned long get_f64_rs(unsigned long insn, u8 fp_reg_offset,
+ struct pt_regs *regs)
+{
+ unsigned long fp_reg = (insn >> fp_reg_offset) & 0x1F;
+ unsigned long val;
+
+ val = get_f64_reg(fp_reg);
+ regs->status |= SR_FS_DIRTY;
+
+ return val;
+}
+
+#endif
+
+extern unsigned long get_f32_reg(unsigned long fp_reg);
+
+static unsigned long get_f32_rs(unsigned long insn, u8 fp_reg_offset,
+ struct pt_regs *regs)
+{
+ unsigned long fp_reg = (insn >> fp_reg_offset) & 0x1F;
+ unsigned long val;
+
+ val = get_f32_reg(fp_reg);
+ regs->status |= SR_FS_DIRTY;
+
+ return val;
+}
+
+#else /* CONFIG_FPU */
+static void set_f32_rd(unsigned long insn, struct pt_regs *regs,
+ unsigned long val) {}
+
+static void set_f64_rd(unsigned long insn, struct pt_regs *regs, u64 val) {}
+
+static unsigned long get_f64_rs(unsigned long insn, u8 fp_reg_offset,
+ struct pt_regs *regs)
+{
+ return 0;
+}
+
+static unsigned long get_f32_rs(unsigned long insn, u8 fp_reg_offset,
+ struct pt_regs *regs)
+{
+ return 0;
+}
+
+#endif
+
+#define GET_F64_RS2(insn, regs) (get_f64_rs(insn, 20, regs))
+#define GET_F64_RS2C(insn, regs) (get_f64_rs(insn, 2, regs))
+#define GET_F64_RS2S(insn, regs) (get_f64_rs(RVC_RS2S(insn), 0, regs))
+
+#define GET_F32_RS2(insn, regs) (get_f32_rs(insn, 20, regs))
+#define GET_F32_RS2C(insn, regs) (get_f32_rs(insn, 2, regs))
+#define GET_F32_RS2S(insn, regs) (get_f32_rs(RVC_RS2S(insn), 0, regs))
+
+#ifdef CONFIG_RISCV_M_MODE
+static inline int load_u8(struct pt_regs *regs, const u8 *addr, u8 *r_val)
+{
+ u8 val;
+
+ asm volatile("lbu %0, %1" : "=&r" (val) : "m" (*addr));
+ *r_val = val;
+
+ return 0;
+}
+
+static inline int store_u8(struct pt_regs *regs, u8 *addr, u8 val)
+{
+ asm volatile ("sb %0, %1\n" : : "r" (val), "m" (*addr));
+
+ return 0;
+}
+
+static inline int get_insn(struct pt_regs *regs, ulong mepc, ulong *r_insn)
+{
+ register ulong __mepc asm ("a2") = mepc;
+ ulong val, rvc_mask = 3, tmp;
+
+ asm ("and %[tmp], %[addr], 2\n"
+ "bnez %[tmp], 1f\n"
+#if defined(CONFIG_64BIT)
+ __stringify(LWU) " %[insn], (%[addr])\n"
+#else
+ __stringify(LW) " %[insn], (%[addr])\n"
+#endif
+ "and %[tmp], %[insn], %[rvc_mask]\n"
+ "beq %[tmp], %[rvc_mask], 2f\n"
+ "sll %[insn], %[insn], %[xlen_minus_16]\n"
+ "srl %[insn], %[insn], %[xlen_minus_16]\n"
+ "j 2f\n"
+ "1:\n"
+ "lhu %[insn], (%[addr])\n"
+ "and %[tmp], %[insn], %[rvc_mask]\n"
+ "bne %[tmp], %[rvc_mask], 2f\n"
+ "lhu %[tmp], 2(%[addr])\n"
+ "sll %[tmp], %[tmp], 16\n"
+ "add %[insn], %[insn], %[tmp]\n"
+ "2:"
+ : [insn] "=&r" (val), [tmp] "=&r" (tmp)
+ : [addr] "r" (__mepc), [rvc_mask] "r" (rvc_mask),
+ [xlen_minus_16] "i" (XLEN_MINUS_16));
+
+ *r_insn = val;
+
+ return 0;
+}
+#else
+static inline int load_u8(struct pt_regs *regs, const u8 *addr, u8 *r_val)
+{
+ if (user_mode(regs)) {
+ return __get_user(*r_val, (u8 __user *)addr);
+ } else {
+ *r_val = *addr;
+ return 0;
+ }
+}
+
+static inline int store_u8(struct pt_regs *regs, u8 *addr, u8 val)
+{
+ if (user_mode(regs)) {
+ return __put_user(val, (u8 __user *)addr);
+ } else {
+ *addr = val;
+ return 0;
+ }
+}
+
+#define __read_insn(regs, insn, insn_addr) \
+({ \
+ int __ret; \
+ \
+ if (user_mode(regs)) { \
+ __ret = __get_user(insn, insn_addr); \
+ } else { \
+ insn = *(__force u16 *)insn_addr; \
+ __ret = 0; \
+ } \
+ \
+ __ret; \
+})
+
+static inline int get_insn(struct pt_regs *regs, ulong epc, ulong *r_insn)
+{
+ ulong insn = 0;
+
+ if (epc & 0x2) {
+ ulong tmp = 0;
+ u16 __user *insn_addr = (u16 __user *)epc;
+
+ if (__read_insn(regs, insn, insn_addr))
+ return -EFAULT;
+ /* __get_user() uses regular "lw" which sign extend the loaded
+ * value make sure to clear higher order bits in case we "or" it
+ * below with the upper 16 bits half.
+ */
+ insn &= GENMASK(15, 0);
+ if ((insn & __INSN_LENGTH_MASK) != __INSN_LENGTH_32) {
+ *r_insn = insn;
+ return 0;
+ }
+ insn_addr++;
+ if (__read_insn(regs, tmp, insn_addr))
+ return -EFAULT;
+ *r_insn = (tmp << 16) | insn;
+
+ return 0;
+ } else {
+ u32 __user *insn_addr = (u32 __user *)epc;
+
+ if (__read_insn(regs, insn, insn_addr))
+ return -EFAULT;
+ if ((insn & __INSN_LENGTH_MASK) == __INSN_LENGTH_32) {
+ *r_insn = insn;
+ return 0;
+ }
+ insn &= GENMASK(15, 0);
+ *r_insn = insn;
+
+ return 0;
+ }
+}
+#endif
+
+union reg_data {
+ u8 data_bytes[8];
+ ulong data_ulong;
+ u64 data_u64;
+};
+
+static bool unaligned_ctl __read_mostly;
+
+/* sysctl hooks */
+int unaligned_enabled __read_mostly = 1; /* Enabled by default */
+
+int handle_misaligned_load(struct pt_regs *regs)
+{
+ union reg_data val;
+ unsigned long epc = regs->epc;
+ unsigned long insn;
+ unsigned long addr = regs->badaddr;
+ int i, fp = 0, shift = 0, len = 0;
+
+ perf_sw_event(PERF_COUNT_SW_ALIGNMENT_FAULTS, 1, regs, addr);
+
+#ifdef CONFIG_RISCV_PROBE_UNALIGNED_ACCESS
+ *this_cpu_ptr(&misaligned_access_speed) = RISCV_HWPROBE_MISALIGNED_EMULATED;
+#endif
+
+ if (!unaligned_enabled)
+ return -1;
+
+ if (user_mode(regs) && (current->thread.align_ctl & PR_UNALIGN_SIGBUS))
+ return -1;
+
+ if (get_insn(regs, epc, &insn))
+ return -1;
+
+ regs->epc = 0;
+
+ if ((insn & INSN_MASK_LW) == INSN_MATCH_LW) {
+ len = 4;
+ shift = 8 * (sizeof(unsigned long) - len);
+#if defined(CONFIG_64BIT)
+ } else if ((insn & INSN_MASK_LD) == INSN_MATCH_LD) {
+ len = 8;
+ shift = 8 * (sizeof(unsigned long) - len);
+ } else if ((insn & INSN_MASK_LWU) == INSN_MATCH_LWU) {
+ len = 4;
+#endif
+ } else if ((insn & INSN_MASK_FLD) == INSN_MATCH_FLD) {
+ fp = 1;
+ len = 8;
+ } else if ((insn & INSN_MASK_FLW) == INSN_MATCH_FLW) {
+ fp = 1;
+ len = 4;
+ } else if ((insn & INSN_MASK_LH) == INSN_MATCH_LH) {
+ len = 2;
+ shift = 8 * (sizeof(unsigned long) - len);
+ } else if ((insn & INSN_MASK_LHU) == INSN_MATCH_LHU) {
+ len = 2;
+#if defined(CONFIG_64BIT)
+ } else if ((insn & INSN_MASK_C_LD) == INSN_MATCH_C_LD) {
+ len = 8;
+ shift = 8 * (sizeof(unsigned long) - len);
+ insn = RVC_RS2S(insn) << SH_RD;
+ } else if ((insn & INSN_MASK_C_LDSP) == INSN_MATCH_C_LDSP &&
+ ((insn >> SH_RD) & 0x1f)) {
+ len = 8;
+ shift = 8 * (sizeof(unsigned long) - len);
+#endif
+ } else if ((insn & INSN_MASK_C_LW) == INSN_MATCH_C_LW) {
+ len = 4;
+ shift = 8 * (sizeof(unsigned long) - len);
+ insn = RVC_RS2S(insn) << SH_RD;
+ } else if ((insn & INSN_MASK_C_LWSP) == INSN_MATCH_C_LWSP &&
+ ((insn >> SH_RD) & 0x1f)) {
+ len = 4;
+ shift = 8 * (sizeof(unsigned long) - len);
+ } else if ((insn & INSN_MASK_C_FLD) == INSN_MATCH_C_FLD) {
+ fp = 1;
+ len = 8;
+ insn = RVC_RS2S(insn) << SH_RD;
+ } else if ((insn & INSN_MASK_C_FLDSP) == INSN_MATCH_C_FLDSP) {
+ fp = 1;
+ len = 8;
+#if defined(CONFIG_32BIT)
+ } else if ((insn & INSN_MASK_C_FLW) == INSN_MATCH_C_FLW) {
+ fp = 1;
+ len = 4;
+ insn = RVC_RS2S(insn) << SH_RD;
+ } else if ((insn & INSN_MASK_C_FLWSP) == INSN_MATCH_C_FLWSP) {
+ fp = 1;
+ len = 4;
+#endif
+ } else {
+ regs->epc = epc;
+ return -1;
+ }
+
+ if (!IS_ENABLED(CONFIG_FPU) && fp)
+ return -EOPNOTSUPP;
+
+ val.data_u64 = 0;
+ for (i = 0; i < len; i++) {
+ if (load_u8(regs, (void *)(addr + i), &val.data_bytes[i]))
+ return -1;
+ }
+
+ if (!fp)
+ SET_RD(insn, regs, val.data_ulong << shift >> shift);
+ else if (len == 8)
+ set_f64_rd(insn, regs, val.data_u64);
+ else
+ set_f32_rd(insn, regs, val.data_ulong);
+
+ regs->epc = epc + INSN_LEN(insn);
+
+ return 0;
+}
+
+int handle_misaligned_store(struct pt_regs *regs)
+{
+ union reg_data val;
+ unsigned long epc = regs->epc;
+ unsigned long insn;
+ unsigned long addr = regs->badaddr;
+ int i, len = 0, fp = 0;
+
+ perf_sw_event(PERF_COUNT_SW_ALIGNMENT_FAULTS, 1, regs, addr);
+
+ if (!unaligned_enabled)
+ return -1;
+
+ if (user_mode(regs) && (current->thread.align_ctl & PR_UNALIGN_SIGBUS))
+ return -1;
+
+ if (get_insn(regs, epc, &insn))
+ return -1;
+
+ regs->epc = 0;
+
+ val.data_ulong = GET_RS2(insn, regs);
+
+ if ((insn & INSN_MASK_SW) == INSN_MATCH_SW) {
+ len = 4;
+#if defined(CONFIG_64BIT)
+ } else if ((insn & INSN_MASK_SD) == INSN_MATCH_SD) {
+ len = 8;
+#endif
+ } else if ((insn & INSN_MASK_FSD) == INSN_MATCH_FSD) {
+ fp = 1;
+ len = 8;
+ val.data_u64 = GET_F64_RS2(insn, regs);
+ } else if ((insn & INSN_MASK_FSW) == INSN_MATCH_FSW) {
+ fp = 1;
+ len = 4;
+ val.data_ulong = GET_F32_RS2(insn, regs);
+ } else if ((insn & INSN_MASK_SH) == INSN_MATCH_SH) {
+ len = 2;
+#if defined(CONFIG_64BIT)
+ } else if ((insn & INSN_MASK_C_SD) == INSN_MATCH_C_SD) {
+ len = 8;
+ val.data_ulong = GET_RS2S(insn, regs);
+ } else if ((insn & INSN_MASK_C_SDSP) == INSN_MATCH_C_SDSP) {
+ len = 8;
+ val.data_ulong = GET_RS2C(insn, regs);
+#endif
+ } else if ((insn & INSN_MASK_C_SW) == INSN_MATCH_C_SW) {
+ len = 4;
+ val.data_ulong = GET_RS2S(insn, regs);
+ } else if ((insn & INSN_MASK_C_SWSP) == INSN_MATCH_C_SWSP) {
+ len = 4;
+ val.data_ulong = GET_RS2C(insn, regs);
+ } else if ((insn & INSN_MASK_C_FSD) == INSN_MATCH_C_FSD) {
+ fp = 1;
+ len = 8;
+ val.data_u64 = GET_F64_RS2S(insn, regs);
+ } else if ((insn & INSN_MASK_C_FSDSP) == INSN_MATCH_C_FSDSP) {
+ fp = 1;
+ len = 8;
+ val.data_u64 = GET_F64_RS2C(insn, regs);
+#if !defined(CONFIG_64BIT)
+ } else if ((insn & INSN_MASK_C_FSW) == INSN_MATCH_C_FSW) {
+ fp = 1;
+ len = 4;
+ val.data_ulong = GET_F32_RS2S(insn, regs);
+ } else if ((insn & INSN_MASK_C_FSWSP) == INSN_MATCH_C_FSWSP) {
+ fp = 1;
+ len = 4;
+ val.data_ulong = GET_F32_RS2C(insn, regs);
+#endif
+ } else {
+ regs->epc = epc;
+ return -1;
+ }
+
+ if (!IS_ENABLED(CONFIG_FPU) && fp)
+ return -EOPNOTSUPP;
+
+ for (i = 0; i < len; i++) {
+ if (store_u8(regs, (void *)(addr + i), val.data_bytes[i]))
+ return -1;
+ }
+
+ regs->epc = epc + INSN_LEN(insn);
+
+ return 0;
+}
+
+static bool check_unaligned_access_emulated(int cpu)
+{
+ long *mas_ptr = per_cpu_ptr(&misaligned_access_speed, cpu);
+ unsigned long tmp_var, tmp_val;
+ bool misaligned_emu_detected;
+
+ *mas_ptr = RISCV_HWPROBE_MISALIGNED_UNKNOWN;
+
+ __asm__ __volatile__ (
+ " "REG_L" %[tmp], 1(%[ptr])\n"
+ : [tmp] "=r" (tmp_val) : [ptr] "r" (&tmp_var) : "memory");
+
+ misaligned_emu_detected = (*mas_ptr == RISCV_HWPROBE_MISALIGNED_EMULATED);
+ /*
+ * If unaligned_ctl is already set, this means that we detected that all
+ * CPUS uses emulated misaligned access at boot time. If that changed
+ * when hotplugging the new cpu, this is something we don't handle.
+ */
+ if (unlikely(unaligned_ctl && !misaligned_emu_detected)) {
+ pr_crit("CPU misaligned accesses non homogeneous (expected all emulated)\n");
+ while (true)
+ cpu_relax();
+ }
+
+ return misaligned_emu_detected;
+}
+
+bool check_unaligned_access_emulated_all_cpus(void)
+{
+ int cpu;
+
+ /*
+ * We can only support PR_UNALIGN controls if all CPUs have misaligned
+ * accesses emulated since tasks requesting such control can run on any
+ * CPU.
+ */
+ for_each_online_cpu(cpu)
+ if (!check_unaligned_access_emulated(cpu))
+ return false;
+
+ unaligned_ctl = true;
+ return true;
+}
+
+bool unaligned_ctl_available(void)
+{
+ return unaligned_ctl;
+}
generated by cgit (git 2.34.1) at 2024-05-09 02:01:15 +0000