Merge tag 'riscv-for-linus-5.14-mw0' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux

Pull RISC-V updates from Palmer Dabbelt:
 "We have a handful of new features for 5.14:

   - Support for transparent huge pages.

   - Support for generic PCI resources mapping.

   - Support for the mem= kernel parameter.

   - Support for KFENCE.

   - A handful of fixes to avoid W+X mappings in the kernel.

   - Support for VMAP_STACK based overflow detection.

   - An optimized copy_{to,from}_user"

* tag 'riscv-for-linus-5.14-mw0' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (37 commits)
  riscv: xip: Fix duplicate included asm/pgtable.h
  riscv: Fix PTDUMP output now BPF region moved back to module region
  riscv: __asm_copy_to-from_user: Optimize unaligned memory access and pipeline stall
  riscv: add VMAP_STACK overflow detection
  riscv: ptrace: add argn syntax
  riscv: mm: fix build errors caused by mk_pmd()
  riscv: Introduce structure that group all variables regarding kernel mapping
  riscv: Map the kernel with correct permissions the first time
  riscv: Introduce set_kernel_memory helper
  riscv: Enable KFENCE for riscv64
  RISC-V: Use asm-generic for {in,out}{bwlq}
  riscv: add ASID-based tlbflushing methods
  riscv: pass the mm_struct to __sbi_tlb_flush_range
  riscv: Add mem kernel parameter support
  riscv: Simplify xip and !xip kernel address conversion macros
  riscv: Remove CONFIG_PHYS_RAM_BASE_FIXED
  riscv: Only initialize swiotlb when necessary
  riscv: fix typo in init.c
  riscv: Cleanup unused functions
  riscv: mm: Use better bitmap_zalloc()
  ...

1 files changed, 35 insertions, 0 deletions

diff --git a/arch/riscv/kernel/traps.c b/arch/riscv/kernel/traps.c
index 7bc88d8aab97..0a98fd0ddfe9 100644
--- a/arch/riscv/kernel/traps.c
+++ b/arch/riscv/kernel/traps.c
@@ -203,3 +203,38 @@ int is_valid_bugaddr(unsigned long pc)
 void __init trap_init(void)
 {
 }
+
+#ifdef CONFIG_VMAP_STACK
+static DEFINE_PER_CPU(unsigned long [OVERFLOW_STACK_SIZE/sizeof(long)],
+		overflow_stack)__aligned(16);
+/*
+ * shadow stack, handled_ kernel_ stack_ overflow(in kernel/entry.S) is used
+ * to get per-cpu overflow stack(get_overflow_stack).
+ */
+long shadow_stack[SHADOW_OVERFLOW_STACK_SIZE/sizeof(long)];
+asmlinkage unsigned long get_overflow_stack(void)
+{
+	return (unsigned long)this_cpu_ptr(overflow_stack) +
+		OVERFLOW_STACK_SIZE;
+}
+
+asmlinkage void handle_bad_stack(struct pt_regs *regs)
+{
+	unsigned long tsk_stk = (unsigned long)current->stack;
+	unsigned long ovf_stk = (unsigned long)this_cpu_ptr(overflow_stack);
+
+	console_verbose();
+
+	pr_emerg("Insufficient stack space to handle exception!\n");
+	pr_emerg("Task stack:     [0x%016lx..0x%016lx]\n",
+			tsk_stk, tsk_stk + THREAD_SIZE);
+	pr_emerg("Overflow stack: [0x%016lx..0x%016lx]\n",
+			ovf_stk, ovf_stk + OVERFLOW_STACK_SIZE);
+
+	__show_regs(regs);
+	panic("Kernel stack overflow");
+
+	for (;;)
+		wait_for_interrupt();
+}
+#endif