Merge tag 'loongarch-fixes-6.1-1' of git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson

Pull LoongArch fixes from Huacai Chen:
 "Remove unused kernel stack padding, fix some build errors/warnings and
  two bugs in laptop platform driver"

* tag 'loongarch-fixes-6.1-1' of git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson:
  platform/loongarch: laptop: Fix possible UAF and simplify generic_acpi_laptop_init()
  platform/loongarch: laptop: Adjust resume order for loongson_hotkey_resume()
  LoongArch: BPF: Avoid declare variables in switch-case
  LoongArch: Use flexible-array member instead of zero-length array
  LoongArch: Remove unused kernel stack padding

6 files changed, 20 insertions, 26 deletions

diff --git a/arch/loongarch/include/asm/processor.h b/arch/loongarch/include/asm/processor.h
index 6954dc5d24e9..7184f1dc61f2 100644
--- a/arch/loongarch/include/asm/processor.h
+++ b/arch/loongarch/include/asm/processor.h
@@ -191,7 +191,7 @@ static inline void flush_thread(void)
 unsigned long __get_wchan(struct task_struct *p);
 
 #define __KSTK_TOS(tsk) ((unsigned long)task_stack_page(tsk) + \
-			 THREAD_SIZE - 32 - sizeof(struct pt_regs))
+			 THREAD_SIZE - sizeof(struct pt_regs))
 #define task_pt_regs(tsk) ((struct pt_regs *)__KSTK_TOS(tsk))
 #define KSTK_EIP(tsk) (task_pt_regs(tsk)->csr_era)
 #define KSTK_ESP(tsk) (task_pt_regs(tsk)->regs[3])
diff --git a/arch/loongarch/include/asm/ptrace.h b/arch/loongarch/include/asm/ptrace.h
index 17838c6b7ccd..59c4608de91d 100644
--- a/arch/loongarch/include/asm/ptrace.h
+++ b/arch/loongarch/include/asm/ptrace.h
@@ -29,7 +29,7 @@ struct pt_regs {
 	unsigned long csr_euen;
 	unsigned long csr_ecfg;
 	unsigned long csr_estat;
-	unsigned long __last[0];
+	unsigned long __last[];
 } __aligned(8);
 
 static inline int regs_irqs_disabled(struct pt_regs *regs)
@@ -133,7 +133,7 @@ static inline void die_if_kernel(const char *str, struct pt_regs *regs)
 #define current_pt_regs()						\
 ({									\
 	unsigned long sp = (unsigned long)__builtin_frame_address(0);	\
-	(struct pt_regs *)((sp | (THREAD_SIZE - 1)) + 1 - 32) - 1;	\
+	(struct pt_regs *)((sp | (THREAD_SIZE - 1)) + 1) - 1;		\
 })
 
 /* Helpers for working with the user stack pointer */
diff --git a/arch/loongarch/kernel/head.S b/arch/loongarch/kernel/head.S
index 97425779ce9f..84970e266658 100644
--- a/arch/loongarch/kernel/head.S
+++ b/arch/loongarch/kernel/head.S
@@ -84,10 +84,9 @@ SYM_CODE_START(kernel_entry)			# kernel entry point
 
 	la.pcrel	tp, init_thread_union
 	/* Set the SP after an empty pt_regs.  */
-	PTR_LI		sp, (_THREAD_SIZE - 32 - PT_SIZE)
+	PTR_LI		sp, (_THREAD_SIZE - PT_SIZE)
 	PTR_ADD		sp, sp, tp
 	set_saved_sp	sp, t0, t1
-	PTR_ADDI	sp, sp, -4 * SZREG	# init stack pointer
 
 	bl		start_kernel
 	ASM_BUG()
diff --git a/arch/loongarch/kernel/process.c b/arch/loongarch/kernel/process.c
index 1256e3582475..2526b68f1c0f 100644
--- a/arch/loongarch/kernel/process.c
+++ b/arch/loongarch/kernel/process.c
@@ -129,7 +129,7 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
 	unsigned long clone_flags = args->flags;
 	struct pt_regs *childregs, *regs = current_pt_regs();
 
-	childksp = (unsigned long)task_stack_page(p) + THREAD_SIZE - 32;
+	childksp = (unsigned long)task_stack_page(p) + THREAD_SIZE;
 
 	/* set up new TSS. */
 	childregs = (struct pt_regs *) childksp - 1;
@@ -236,7 +236,7 @@ bool in_task_stack(unsigned long stack, struct task_struct *task,
 			struct stack_info *info)
 {
 	unsigned long begin = (unsigned long)task_stack_page(task);
-	unsigned long end = begin + THREAD_SIZE - 32;
+	unsigned long end = begin + THREAD_SIZE;
 
 	if (stack < begin || stack >= end)
 		return false;
diff --git a/arch/loongarch/kernel/switch.S b/arch/loongarch/kernel/switch.S
index 43ebbc3990f7..202a163cb32f 100644
--- a/arch/loongarch/kernel/switch.S
+++ b/arch/loongarch/kernel/switch.S
@@ -26,7 +26,7 @@ SYM_FUNC_START(__switch_to)
 	move	tp, a2
 	cpu_restore_nonscratch a1
 
-	li.w		t0, _THREAD_SIZE - 32
+	li.w		t0, _THREAD_SIZE
 	PTR_ADD		t0, t0, tp
 	set_saved_sp	t0, t1, t2
 
diff --git a/arch/loongarch/net/bpf_jit.c b/arch/loongarch/net/bpf_jit.c
index 43f0a98efe38..bdcd0c7719a9 100644
--- a/arch/loongarch/net/bpf_jit.c
+++ b/arch/loongarch/net/bpf_jit.c
@@ -279,6 +279,7 @@ static void emit_atomic(const struct bpf_insn *insn, struct jit_ctx *ctx)
 	const u8 t1 = LOONGARCH_GPR_T1;
 	const u8 t2 = LOONGARCH_GPR_T2;
 	const u8 t3 = LOONGARCH_GPR_T3;
+	const u8 r0 = regmap[BPF_REG_0];
 	const u8 src = regmap[insn->src_reg];
 	const u8 dst = regmap[insn->dst_reg];
 	const s16 off = insn->off;
@@ -359,8 +360,6 @@ static void emit_atomic(const struct bpf_insn *insn, struct jit_ctx *ctx)
 		break;
 	/* r0 = atomic_cmpxchg(dst + off, r0, src); */
 	case BPF_CMPXCHG:
-		u8 r0 = regmap[BPF_REG_0];
-
 		move_reg(ctx, t2, r0);
 		if (isdw) {
 			emit_insn(ctx, lld, r0, t1, 0);
@@ -390,8 +389,11 @@ static bool is_signed_bpf_cond(u8 cond)
 
 static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, bool extra_pass)
 {
-	const bool is32 = BPF_CLASS(insn->code) == BPF_ALU ||
-			  BPF_CLASS(insn->code) == BPF_JMP32;
+	u8 tm = -1;
+	u64 func_addr;
+	bool func_addr_fixed;
+	int i = insn - ctx->prog->insnsi;
+	int ret, jmp_offset;
 	const u8 code = insn->code;
 	const u8 cond = BPF_OP(code);
 	const u8 t1 = LOONGARCH_GPR_T1;
@@ -400,8 +402,8 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, bool ext
 	const u8 dst = regmap[insn->dst_reg];
 	const s16 off = insn->off;
 	const s32 imm = insn->imm;
-	int jmp_offset;
-	int i = insn - ctx->prog->insnsi;
+	const u64 imm64 = (u64)(insn + 1)->imm << 32 | (u32)insn->imm;
+	const bool is32 = BPF_CLASS(insn->code) == BPF_ALU || BPF_CLASS(insn->code) == BPF_JMP32;
 
 	switch (code) {
 	/* dst = src */
@@ -724,24 +726,23 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, bool ext
 	case BPF_JMP32 | BPF_JSGE | BPF_K:
 	case BPF_JMP32 | BPF_JSLT | BPF_K:
 	case BPF_JMP32 | BPF_JSLE | BPF_K:
-		u8 t7 = -1;
 		jmp_offset = bpf2la_offset(i, off, ctx);
 		if (imm) {
 			move_imm(ctx, t1, imm, false);
-			t7 = t1;
+			tm = t1;
 		} else {
 			/* If imm is 0, simply use zero register. */
-			t7 = LOONGARCH_GPR_ZERO;
+			tm = LOONGARCH_GPR_ZERO;
 		}
 		move_reg(ctx, t2, dst);
 		if (is_signed_bpf_cond(BPF_OP(code))) {
-			emit_sext_32(ctx, t7, is32);
+			emit_sext_32(ctx, tm, is32);
 			emit_sext_32(ctx, t2, is32);
 		} else {
-			emit_zext_32(ctx, t7, is32);
+			emit_zext_32(ctx, tm, is32);
 			emit_zext_32(ctx, t2, is32);
 		}
-		if (emit_cond_jmp(ctx, cond, t2, t7, jmp_offset) < 0)
+		if (emit_cond_jmp(ctx, cond, t2, tm, jmp_offset) < 0)
 			goto toofar;
 		break;
 
@@ -775,10 +776,6 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, bool ext
 
 	/* function call */
 	case BPF_JMP | BPF_CALL:
-		int ret;
-		u64 func_addr;
-		bool func_addr_fixed;
-
 		mark_call(ctx);
 		ret = bpf_jit_get_func_addr(ctx->prog, insn, extra_pass,
 					    &func_addr, &func_addr_fixed);
@@ -811,8 +808,6 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, bool ext
 
 	/* dst = imm64 */
 	case BPF_LD | BPF_IMM | BPF_DW:
-		u64 imm64 = (u64)(insn + 1)->imm << 32 | (u32)insn->imm;
-
 		move_imm(ctx, dst, imm64, is32);
 		return 1;