Merge tag 'riscv-fixes-6.15-rc6' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/alexghiti/linux into fixes

riscv fixes for 6.15-rc6

- A fix to handle compressed halfword load/store instructions misaligned accesses
- A fix to allow user memory access while handling a misaligned access
- 2 fixes to return an error if the pointer masking extension is not implemented on the platform but userspace still tries to access it, which caused oops on some early platforms
- A fix to prevent the stripping of .rela.dyn so that a vmlinux loaded by kexec can successfully boot

* tag 'riscv-fixes-6.15-rc6' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/alexghiti/linux:
  riscv: Disallow PR_GET_TAGGED_ADDR_CTRL without Supm
  scripts: Do not strip .rela.dyn section
  riscv: Fix kernel crash due to PR_SET_TAGGED_ADDR_CTRL
  riscv: misaligned: use get_user() instead of __get_user()
  riscv: misaligned: enable IRQs while handling misaligned accesses
  riscv: misaligned: factorize trap handling
  riscv: misaligned: Add handling for ZCB instructions

Author: palmer-dabbelt

arch/riscv/kernel/process.c

@@ -275,6 +275,9 @@ long set_tagged_addr_ctrl(struct task_struct *task, unsigned long arg)
 	unsigned long pmm;
 	u8 pmlen;
 
+	if (!riscv_has_extension_unlikely(RISCV_ISA_EXT_SUPM))
+		return -EINVAL;
+
 	if (is_compat_thread(ti))
 		return -EINVAL;
 
@@ -330,6 +333,9 @@ long get_tagged_addr_ctrl(struct task_struct *task)
 	struct thread_info *ti = task_thread_info(task);
 	long ret = 0;
 
+	if (!riscv_has_extension_unlikely(RISCV_ISA_EXT_SUPM))
+		return -EINVAL;
+
 	if (is_compat_thread(ti))
 		return -EINVAL;
 

arch/riscv/kernel/traps.c

@@ -198,47 +198,57 @@ asmlinkage __visible __trap_section void do_trap_insn_illegal(struct pt_regs *re
 DO_ERROR_INFO(do_trap_load_fault,
 	SIGSEGV, SEGV_ACCERR, "load access fault");
 
-asmlinkage __visible __trap_section void do_trap_load_misaligned(struct pt_regs *regs)
+enum misaligned_access_type {
+	MISALIGNED_STORE,
+	MISALIGNED_LOAD,
+};
+static const struct {
+	const char *type_str;
+	int (*handler)(struct pt_regs *regs);
+} misaligned_handler[] = {
+	[MISALIGNED_STORE] = {
+		.type_str = "Oops - store (or AMO) address misaligned",
+		.handler = handle_misaligned_store,
+	},
+	[MISALIGNED_LOAD] = {
+		.type_str = "Oops - load address misaligned",
+		.handler = handle_misaligned_load,
+	},
+};
+
+static void do_trap_misaligned(struct pt_regs *regs, enum misaligned_access_type type)
 {
+	irqentry_state_t state;
+
 	if (user_mode(regs)) {
 		irqentry_enter_from_user_mode(regs);
+		local_irq_enable();
+	} else {
+		state = irqentry_nmi_enter(regs);
+	}
 
-		if (handle_misaligned_load(regs))
-			do_trap_error(regs, SIGBUS, BUS_ADRALN, regs->epc,
-			      "Oops - load address misaligned");
+	if (misaligned_handler[type].handler(regs))
+		do_trap_error(regs, SIGBUS, BUS_ADRALN, regs->epc,
+			      misaligned_handler[type].type_str);
 
+	if (user_mode(regs)) {
+		local_irq_disable();
 		irqentry_exit_to_user_mode(regs);
 	} else {
-		irqentry_state_t state = irqentry_nmi_enter(regs);
-
-		if (handle_misaligned_load(regs))
-			do_trap_error(regs, SIGBUS, BUS_ADRALN, regs->epc,
-			      "Oops - load address misaligned");
-
 		irqentry_nmi_exit(regs, state);
 	}
 }
 
-asmlinkage __visible __trap_section void do_trap_store_misaligned(struct pt_regs *regs)
+asmlinkage __visible __trap_section void do_trap_load_misaligned(struct pt_regs *regs)
 {
-	if (user_mode(regs)) {
-		irqentry_enter_from_user_mode(regs);
-
-		if (handle_misaligned_store(regs))
-			do_trap_error(regs, SIGBUS, BUS_ADRALN, regs->epc,
-				"Oops - store (or AMO) address misaligned");
-
-		irqentry_exit_to_user_mode(regs);
-	} else {
-		irqentry_state_t state = irqentry_nmi_enter(regs);
-
-		if (handle_misaligned_store(regs))
-			do_trap_error(regs, SIGBUS, BUS_ADRALN, regs->epc,
-				"Oops - store (or AMO) address misaligned");
+	do_trap_misaligned(regs, MISALIGNED_LOAD);
+}
 
-		irqentry_nmi_exit(regs, state);
-	}
+asmlinkage __visible __trap_section void do_trap_store_misaligned(struct pt_regs *regs)
+{
+	do_trap_misaligned(regs, MISALIGNED_STORE);
 }
+
 DO_ERROR_INFO(do_trap_store_fault,
 	SIGSEGV, SEGV_ACCERR, "store (or AMO) access fault");
 DO_ERROR_INFO(do_trap_ecall_s,

arch/riscv/kernel/traps_misaligned.c

@@ -88,6 +88,13 @@
 #define INSN_MATCH_C_FSWSP		0xe002
 #define INSN_MASK_C_FSWSP		0xe003
 
+#define INSN_MATCH_C_LHU		0x8400
+#define INSN_MASK_C_LHU			0xfc43
+#define INSN_MATCH_C_LH			0x8440
+#define INSN_MASK_C_LH			0xfc43
+#define INSN_MATCH_C_SH			0x8c00
+#define INSN_MASK_C_SH			0xfc43
+
 #define INSN_LEN(insn)			((((insn) & 0x3) < 0x3) ? 2 : 4)
 
 #if defined(CONFIG_64BIT)
@@ -268,7 +275,7 @@ static unsigned long get_f32_rs(unsigned long insn, u8 fp_reg_offset,
 	int __ret;					\
 							\
 	if (user_mode(regs)) {				\
-		__ret = __get_user(insn, (type __user *) insn_addr); \
+		__ret = get_user(insn, (type __user *) insn_addr); \
 	} else {					\
 		insn = *(type *)insn_addr;		\
 		__ret = 0;				\
@@ -431,6 +438,13 @@ static int handle_scalar_misaligned_load(struct pt_regs *regs)
 		fp = 1;
 		len = 4;
 #endif
+	} else if ((insn & INSN_MASK_C_LHU) == INSN_MATCH_C_LHU) {
+		len = 2;
+		insn = RVC_RS2S(insn) << SH_RD;
+	} else if ((insn & INSN_MASK_C_LH) == INSN_MATCH_C_LH) {
+		len = 2;
+		shift = 8 * (sizeof(ulong) - len);
+		insn = RVC_RS2S(insn) << SH_RD;
 	} else {
 		regs->epc = epc;
 		return -1;
@@ -530,6 +544,9 @@ static int handle_scalar_misaligned_store(struct pt_regs *regs)
 		len = 4;
 		val.data_ulong = GET_F32_RS2C(insn, regs);
 #endif
+	} else if ((insn & INSN_MASK_C_SH) == INSN_MATCH_C_SH) {
+		len = 2;
+		val.data_ulong = GET_RS2S(insn, regs);
 	} else {
 		regs->epc = epc;
 		return -1;

scripts/Makefile.vmlinux

@@ -13,7 +13,7 @@ ifdef CONFIG_ARCH_VMLINUX_NEEDS_RELOCS
 vmlinux-final := vmlinux.unstripped
 
 quiet_cmd_strip_relocs = RSTRIP  $@
-      cmd_strip_relocs = $(OBJCOPY) --remove-section='.rel*' $< $@
+      cmd_strip_relocs = $(OBJCOPY) --remove-section='.rel*' --remove-section=!'.rel*.dyn' $< $@
 
 vmlinux: $(vmlinux-final) FORCE
 	$(call if_changed,strip_relocs)