Merge tag 'riscv-for-linus-6.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux

Pull RISC-V updates from Palmer Dabbelt:

 - Support for cbo.zero in userspace

 - Support for CBOs on ACPI-based systems

 - A handful of improvements for the T-Head cache flushing ops

 - Support for software shadow call stacks

 - Various cleanups and fixes

* tag 'riscv-for-linus-6.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (31 commits)
  RISC-V: hwprobe: Fix vDSO SIGSEGV
  riscv: configs: defconfig: Enable configs required for RZ/Five SoC
  riscv: errata: prefix T-Head mnemonics with th.
  riscv: put interrupt entries into .irqentry.text
  riscv: mm: Update the comment of CONFIG_PAGE_OFFSET
  riscv: Using TOOLCHAIN_HAS_ZIHINTPAUSE marco replace zihintpause
  riscv/mm: Fix the comment for swap pte format
  RISC-V: clarify the QEMU workaround in ISA parser
  riscv: correct pt_level name via pgtable_l5/4_enabled
  RISC-V: Provide pgtable_l5_enabled on rv32
  clocksource: timer-riscv: Increase rating of clock_event_device for Sstc
  clocksource: timer-riscv: Don't enable/disable timer interrupt
  lkdtm: Fix CFI_BACKWARD on RISC-V
  riscv: Use separate IRQ shadow call stacks
  riscv: Implement Shadow Call Stack
  riscv: Move global pointer loading to a macro
  riscv: Deduplicate IRQ stack switching
  riscv: VMAP_STACK overflow detection thread-safe
  RISC-V: cacheflush: Initialize CBO variables on ACPI systems
  RISC-V: ACPI: RHCT: Add function to get CBO block sizes
  ...

1 files changed, 12 insertions, 5 deletions

diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
index e3803822ab5a..7aeba01dcfd4 100644
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -93,10 +93,10 @@ static bool riscv_isa_extension_check(int id)
 		return true;
 	case RISCV_ISA_EXT_ZICBOZ:
 		if (!riscv_cboz_block_size) {
-			pr_err("Zicboz detected in ISA string, but no cboz-block-size found\n");
+			pr_err("Zicboz detected in ISA string, disabling as no cboz-block-size found\n");
 			return false;
 		} else if (!is_power_of_2(riscv_cboz_block_size)) {
-			pr_err("cboz-block-size present, but is not a power-of-2\n");
+			pr_err("Zicboz disabled as cboz-block-size present, but is not a power-of-2\n");
 			return false;
 		}
 		return true;
@@ -206,10 +206,11 @@ static void __init riscv_parse_isa_string(unsigned long *this_hwcap, struct risc
 		switch (*ext) {
 		case 's':
 			/*
-			 * Workaround for invalid single-letter 's' & 'u'(QEMU).
+			 * Workaround for invalid single-letter 's' & 'u' (QEMU).
 			 * No need to set the bit in riscv_isa as 's' & 'u' are
-			 * not valid ISA extensions. It works until multi-letter
-			 * extension starting with "Su" appears.
+			 * not valid ISA extensions. It works unless the first
+			 * multi-letter extension in the ISA string begins with
+			 * "Su" and is not prefixed with an underscore.
 			 */
 			if (ext[-1] != '_' && ext[1] == 'u') {
 				++isa;
@@ -655,6 +656,12 @@ static int check_unaligned_access_boot_cpu(void)
 
 arch_initcall(check_unaligned_access_boot_cpu);
 
+void riscv_user_isa_enable(void)
+{
+	if (riscv_cpu_has_extension_unlikely(smp_processor_id(), RISCV_ISA_EXT_ZICBOZ))
+		csr_set(CSR_SENVCFG, ENVCFG_CBZE);
+}
+
 #ifdef CONFIG_RISCV_ALTERNATIVE
 /*
  * Alternative patch sites consider 48 bits when determining when to patch