Merge tag 'loongarch-6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson

Pull LoongArch updates from Huacai Chen:

 - Switch to relative exception tables

 - Add unaligned access support

 - Add alternative runtime patching mechanism

 - Add FDT booting support from efi system table

 - Add suspend/hibernation (ACPI S3/S4) support

 - Add basic STACKPROTECTOR support

 - Add ftrace (function tracer) support

 - Update the default config file

* tag 'loongarch-6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson: (24 commits)
  LoongArch: Update Loongson-3 default config file
  LoongArch: modules/ftrace: Initialize PLT at load time
  LoongArch/ftrace: Add HAVE_FUNCTION_GRAPH_RET_ADDR_PTR support
  LoongArch/ftrace: Add HAVE_DYNAMIC_FTRACE_WITH_ARGS support
  LoongArch/ftrace: Add HAVE_DYNAMIC_FTRACE_WITH_REGS support
  LoongArch/ftrace: Add dynamic function graph tracer support
  LoongArch/ftrace: Add dynamic function tracer support
  LoongArch/ftrace: Add recordmcount support
  LoongArch/ftrace: Add basic support
  LoongArch: module: Use got/plt section indices for relocations
  LoongArch: Add basic STACKPROTECTOR support
  LoongArch: Add hibernation (ACPI S4) support
  LoongArch: Add suspend (ACPI S3) support
  LoongArch: Add processing ISA Node in DeviceTree
  LoongArch: Add FDT booting support from efi system table
  LoongArch: Use alternative to optimize libraries
  LoongArch: Add alternative runtime patching mechanism
  LoongArch: Add unaligned access support
  LoongArch: BPF: Add BPF exception tables
  LoongArch: Remove the .fixup section usage
  ...

1 files changed, 50 insertions, 9 deletions

diff --git a/arch/loongarch/mm/extable.c b/arch/loongarch/mm/extable.c
index bc20988f2b87..9ab69872dcff 100644
--- a/arch/loongarch/mm/extable.c
+++ b/arch/loongarch/mm/extable.c
@@ -2,21 +2,62 @@
 /*
  * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
  */
+#include <linux/bitfield.h>
 #include <linux/extable.h>
-#include <linux/spinlock.h>
-#include <asm/branch.h>
 #include <linux/uaccess.h>
+#include <asm/asm-extable.h>
+#include <asm/branch.h>
+
+static inline unsigned long
+get_ex_fixup(const struct exception_table_entry *ex)
+{
+	return ((unsigned long)&ex->fixup + ex->fixup);
+}
+
+static inline void regs_set_gpr(struct pt_regs *regs,
+				unsigned int offset, unsigned long val)
+{
+	if (offset && offset <= MAX_REG_OFFSET)
+		*(unsigned long *)((unsigned long)regs + offset) = val;
+}
+
+static bool ex_handler_fixup(const struct exception_table_entry *ex,
+			     struct pt_regs *regs)
+{
+	regs->csr_era = get_ex_fixup(ex);
+
+	return true;
+}
+
+static bool ex_handler_uaccess_err_zero(const struct exception_table_entry *ex,
+					struct pt_regs *regs)
+{
+	int reg_err = FIELD_GET(EX_DATA_REG_ERR, ex->data);
+	int reg_zero = FIELD_GET(EX_DATA_REG_ZERO, ex->data);
+
+	regs_set_gpr(regs, reg_err * sizeof(unsigned long), -EFAULT);
+	regs_set_gpr(regs, reg_zero * sizeof(unsigned long), 0);
+	regs->csr_era = get_ex_fixup(ex);
+
+	return true;
+}
 
-int fixup_exception(struct pt_regs *regs)
+bool fixup_exception(struct pt_regs *regs)
 {
-	const struct exception_table_entry *fixup;
+	const struct exception_table_entry *ex;
 
-	fixup = search_exception_tables(exception_era(regs));
-	if (fixup) {
-		regs->csr_era = fixup->fixup;
+	ex = search_exception_tables(exception_era(regs));
+	if (!ex)
+		return false;
 
-		return 1;
+	switch (ex->type) {
+	case EX_TYPE_FIXUP:
+		return ex_handler_fixup(ex, regs);
+	case EX_TYPE_UACCESS_ERR_ZERO:
+		return ex_handler_uaccess_err_zero(ex, regs);
+	case EX_TYPE_BPF:
+		return ex_handler_bpf(ex, regs);
 	}
 
-	return 0;
+	BUG();
 }