Merge tag 'riscv-for-linus-5.9-mw0' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux

Pull RISC-V updates from Palmer Dabbelt:
 "We have a lot of new kernel features for this merge window:

   - ARCH_SUPPORTS_ATOMIC_RMW, to allow OSQ locks to be enabled

   - The ability to enable NO_HZ_FULL

   - Support for enabling kcov, kmemleak, stack protector, and VM
     debugging

   - JUMP_LABEL support

  There are also a handful of cleanups"

* tag 'riscv-for-linus-5.9-mw0' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (24 commits)
  riscv: disable stack-protector for vDSO
  RISC-V: Fix build warning for smpboot.c
  riscv: fix build warning of mm/pageattr
  riscv: Fix build warning for mm/init
  RISC-V: Setup exception vector early
  riscv: Select ARCH_HAS_DEBUG_VM_PGTABLE
  riscv: Use generic pgprot_* macros from <linux/pgtable.h>
  mm: pgtable: Make generic pgprot_* macros available for no-MMU
  riscv: Cleanup unnecessary define in asm-offset.c
  riscv: Add jump-label implementation
  riscv: Support R_RISCV_ADD64 and R_RISCV_SUB64 relocs
  Replace HTTP links with HTTPS ones: RISC-V
  riscv: Add STACKPROTECTOR supported
  riscv: Fix typo in asm/hwcap.h uapi header
  riscv: Add kmemleak support
  riscv: Allow building with kcov coverage
  riscv: Enable context tracking
  riscv: Support irq_work via self IPIs
  riscv: Enable LOCKDEP_SUPPORT & fixup TRACE_IRQFLAGS_SUPPORT
  riscv: Fixup lockdep_assert_held with wrong param cpu_running
  ...

1 files changed, 33 insertions, 0 deletions

diff --git a/arch/riscv/include/asm/stackprotector.h b/arch/riscv/include/asm/stackprotector.h
new file mode 100644
index 000000000000..d95f7b2a7f37
--- /dev/null
+++ b/arch/riscv/include/asm/stackprotector.h
@@ -0,0 +1,33 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef _ASM_RISCV_STACKPROTECTOR_H
+#define _ASM_RISCV_STACKPROTECTOR_H
+
+#include <linux/random.h>
+#include <linux/version.h>
+#include <asm/timex.h>
+
+extern unsigned long __stack_chk_guard;
+
+/*
+ * Initialize the stackprotector canary value.
+ *
+ * NOTE: this must only be called from functions that never return,
+ * and it must always be inlined.
+ */
+static __always_inline void boot_init_stack_canary(void)
+{
+	unsigned long canary;
+	unsigned long tsc;
+
+	/* Try to get a semi random initial value. */
+	get_random_bytes(&canary, sizeof(canary));
+	tsc = get_cycles();
+	canary += tsc + (tsc << BITS_PER_LONG/2);
+	canary ^= LINUX_VERSION_CODE;
+	canary &= CANARY_MASK;
+
+	current->stack_canary = canary;
+	__stack_chk_guard = current->stack_canary;
+}
+#endif /* _ASM_RISCV_STACKPROTECTOR_H */