From 441381506ba7ca1cb8b44e651b130ab791d2e298 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Cl=C3=A9ment=20L=C3=A9ger?= Date: Tue, 6 Feb 2024 16:40:59 +0100 Subject: [PATCH] riscv: misaligned: remove CONFIG_RISCV_M_MODE specific code MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit While reworking code to fix sparse errors, it appears that the RISCV_M_MODE specific could actually be removed and use the one for normal mode. Even though RISCV_M_MODE can do direct user memory access, using the user uaccess helpers is also going to work. Since there is no need anymore for specific accessors (load_u8()/store_u8()), we can directly use memcpy()/copy_{to/from}_user() and get rid of the copy loop entirely. __read_insn() is also fixed to use an unsigned long instead of a pointer which was cast in __user address space. The insn_addr parameter is now cast from unsigned lnog to the correct address space directly. Signed-off-by: Clément Léger Reviewed-by: Charlie Jenkins Link: https://lore.kernel.org/r/20240206154104.896809-1-cleger@rivosinc.com Signed-off-by: Palmer Dabbelt --- arch/riscv/kernel/traps_misaligned.c | 106 +++++---------------------- 1 file changed, 17 insertions(+), 89 deletions(-) diff --git a/arch/riscv/kernel/traps_misaligned.c b/arch/riscv/kernel/traps_misaligned.c index 2adb7c3e4dd5..b62d5a2f4541 100644 --- a/arch/riscv/kernel/traps_misaligned.c +++ b/arch/riscv/kernel/traps_misaligned.c @@ -264,86 +264,14 @@ static unsigned long get_f32_rs(unsigned long insn, u8 fp_reg_offset, #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) \ +#define __read_insn(regs, insn, insn_addr, type) \ ({ \ int __ret; \ \ if (user_mode(regs)) { \ - __ret = __get_user(insn, insn_addr); \ + __ret = __get_user(insn, (type __user *) insn_addr); \ } else { \ - insn = *(__force u16 *)insn_addr; \ + insn = *(type *)insn_addr; \ __ret = 0; \ } \ \ @@ -356,9 +284,8 @@ static inline int get_insn(struct pt_regs *regs, ulong epc, ulong *r_insn) if (epc & 0x2) { ulong tmp = 0; - u16 __user *insn_addr = (u16 __user *)epc; - if (__read_insn(regs, insn, insn_addr)) + if (__read_insn(regs, insn, epc, u16)) 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 @@ -369,16 +296,14 @@ static inline int get_insn(struct pt_regs *regs, ulong epc, ulong *r_insn) *r_insn = insn; return 0; } - insn_addr++; - if (__read_insn(regs, tmp, insn_addr)) + epc += sizeof(u16); + if (__read_insn(regs, tmp, epc, u16)) return -EFAULT; *r_insn = (tmp << 16) | insn; return 0; } else { - u32 __user *insn_addr = (u32 __user *)epc; - - if (__read_insn(regs, insn, insn_addr)) + if (__read_insn(regs, insn, epc, u32)) return -EFAULT; if ((insn & __INSN_LENGTH_MASK) == __INSN_LENGTH_32) { *r_insn = insn; @@ -390,7 +315,6 @@ static inline int get_insn(struct pt_regs *regs, ulong epc, ulong *r_insn) return 0; } } -#endif union reg_data { u8 data_bytes[8]; @@ -409,7 +333,7 @@ int handle_misaligned_load(struct pt_regs *regs) unsigned long epc = regs->epc; unsigned long insn; unsigned long addr = regs->badaddr; - int i, fp = 0, shift = 0, len = 0; + int fp = 0, shift = 0, len = 0; perf_sw_event(PERF_COUNT_SW_ALIGNMENT_FAULTS, 1, regs, addr); @@ -492,9 +416,11 @@ int handle_misaligned_load(struct pt_regs *regs) return -EOPNOTSUPP; val.data_u64 = 0; - for (i = 0; i < len; i++) { - if (load_u8(regs, (void *)(addr + i), &val.data_bytes[i])) + if (user_mode(regs)) { + if (raw_copy_from_user(&val, (u8 __user *)addr, len)) return -1; + } else { + memcpy(&val, (u8 *)addr, len); } if (!fp) @@ -515,7 +441,7 @@ int handle_misaligned_store(struct pt_regs *regs) unsigned long epc = regs->epc; unsigned long insn; unsigned long addr = regs->badaddr; - int i, len = 0, fp = 0; + int len = 0, fp = 0; perf_sw_event(PERF_COUNT_SW_ALIGNMENT_FAULTS, 1, regs, addr); @@ -588,9 +514,11 @@ int handle_misaligned_store(struct pt_regs *regs) 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])) + if (user_mode(regs)) { + if (raw_copy_to_user((u8 __user *)addr, &val, len)) return -1; + } else { + memcpy((u8 *)addr, &val, len); } regs->epc = epc + INSN_LEN(insn);