diff --git a/arch/loongarch/kernel/unaligned.c b/arch/loongarch/kernel/unaligned.c index 3abf163dd..1063cb788 100644 --- a/arch/loongarch/kernel/unaligned.c +++ b/arch/loongarch/kernel/unaligned.c @@ -27,12 +27,60 @@ static u32 unaligned_instructions_user; static u32 unaligned_instructions_kernel; #endif +static inline unsigned long read_fpr(unsigned int idx); +static inline void write_fpr(unsigned int idx, unsigned long value); + +/* + * Temporarily enable the FPU while touching hardware FP registers. + * The exception entry disables EUEN, so using base FP instructions in the + * unaligned-access emulator would otherwise trigger an FPD exception. + */ +static inline unsigned long read_fpr_hw(unsigned int idx) +{ + unsigned long value; + + preempt_disable(); + value = read_fpr(idx); + preempt_enable(); + + return value; +} + +static inline void write_fpr_hw(unsigned int idx, unsigned long value) +{ + preempt_disable(); + write_fpr(idx, value); + preempt_enable(); +} + static inline unsigned long read_fpr(unsigned int idx) { #define READ_FPR(idx, __value) \ __asm__ __volatile__("movfr2gr.d %0, $f"#idx"\n\t" : "=r"(__value)); unsigned long __value; + unsigned int ori_euen_fpu; + unsigned int ori_CRMD_IE; + + ori_CRMD_IE = 0; + __asm__ volatile ( + "addi.d %0, $zero, 0x0\t\n" + "addi.d $t2, $zero, 0x4\t\n" + "csrxchg %0, $t2, 0x0\t\n" + : "+r"(ori_CRMD_IE) + : + : "$t2" + ); + + ori_euen_fpu = 0; + __asm__ volatile ( + "addi.d %0, $zero, 0x1\t\n" + "addi.d $t2, $zero, 0x1\t\n" + "csrxchg %0, $t2, 0x2\t\n" + : "+r"(ori_euen_fpu) + : + : "$t2" + ); switch (idx) { case 0: @@ -134,6 +182,21 @@ static inline unsigned long read_fpr(unsigned int idx) default: panic("unexpected idx '%d'", idx); } + __asm__ volatile ( + "addi.d $t2, $zero, 0x1\t\n" + "csrxchg %0, $t2, 0x2\t\n" + : + : "r"(ori_euen_fpu) + : "$t2" + ); + + __asm__ volatile ( + "addi.d $t2, $zero, 0x4\t\n" + "csrxchg %0, $t2, 0x0\t\n" + : + : "r"(ori_CRMD_IE) + : "$t2" + ); #undef READ_FPR return __value; } @@ -143,6 +206,29 @@ static inline void write_fpr(unsigned int idx, unsigned long value) #define WRITE_FPR(idx, value) \ __asm__ __volatile__("movgr2fr.d $f"#idx", %0\n\t" :: "r"(value)); + unsigned int ori_euen_fpu; + unsigned int ori_CRMD_IE; + + ori_CRMD_IE = 0; + __asm__ volatile ( + "addi.d %0, $zero, 0x0\t\n" + "addi.d $t2, $zero, 0x4\t\n" + "csrxchg %0, $t2, 0x0\t\n" + : "+r"(ori_CRMD_IE) + : + : "$t2" + ); + + ori_euen_fpu = 0; + __asm__ volatile ( + "addi.d %0, $zero, 0x1\t\n" + "addi.d $t2, $zero, 0x1\t\n" + "csrxchg %0, $t2, 0x2\t\n" + : "+r"(ori_euen_fpu) + : + : "$t2" + ); + switch (idx) { case 0: WRITE_FPR(0, value); @@ -243,6 +329,22 @@ static inline void write_fpr(unsigned int idx, unsigned long value) default: panic("unexpected idx '%d'", idx); } + __asm__ volatile ( + "addi.d $t2, $zero, 0x1\t\n" + "csrxchg %0, $t2, 0x2\t\n" + : + : "r"(ori_euen_fpu) + : "$t2" + ); + + __asm__ volatile ( + "addi.d $t2, $zero, 0x4\t\n" + "csrxchg %0, $t2, 0x0\t\n" + : + : "r"(ori_CRMD_IE) + : "$t2" + ); + #undef WRITE_FPR } @@ -431,7 +533,7 @@ void emulate_load_store_insn(struct pt_regs *regs, void __user *addr, unsigned i regs->regs[insn.reg3_format.rd] = value; else { if (is_fpu_owner()) - write_fpr(insn.reg3_format.rd, value); + write_fpr_hw(insn.reg3_format.rd, value); else set_fpr64(¤t->thread.fpu.fpr[insn.reg3_format.rd], 0, value); } @@ -441,7 +543,7 @@ void emulate_load_store_insn(struct pt_regs *regs, void __user *addr, unsigned i value = regs->regs[insn.reg3_format.rd]; else { if (is_fpu_owner()) - value = read_fpr(insn.reg3_format.rd); + value = read_fpr_hw(insn.reg3_format.rd); else value = get_fpr64(¤t->thread.fpu.fpr[insn.reg3_format.rd], 0); }