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Merge tag 'riscv-for-linus-v7.0-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux

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Pull RISC-V updates from Paul Walmsley:
 "Before v7.0 is released, fix a few issues with the CFI patchset,
  merged earlier in v7.0-rc, that primarily affect interfaces to
  non-kernel code:

   - Improve the prctl() interface for per-task indirect branch landing
     pad control to expand abbreviations and to resemble the speculation
     control prctl() interface

   - Expand the "LP" and "SS" abbreviations in the ptrace uapi header
     file to "branch landing pad" and "shadow stack", to improve
     readability

   - Fix a typo in a CFI-related macro name in the ptrace uapi header
     file

   - Ensure that the indirect branch tracking state and shadow stack
     state are unlocked immediately after an exec() on the new task so
     that libc subsequently can control it

   - While working in this area, clean up the kernel-internal,
     cross-architecture prctl() function names by expanding the
     abbreviations mentioned above"

* tag 'riscv-for-linus-v7.0-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
  prctl: cfi: change the branch landing pad prctl()s to be more descriptive
  riscv: ptrace: cfi: expand "SS" references to "shadow stack" in uapi headers
  prctl: rename branch landing pad implementation functions to be more explicit
  riscv: ptrace: expand "LP" references to "branch landing pads" in uapi headers
  riscv: cfi: clear CFI lock status in start_thread()
  riscv: ptrace: cfi: fix "PRACE" typo in uapi header
This commit is contained in:
Linus Torvalds
2026-04-10 17:27:08 -07:00
parent c43adb3613 08ee155905
commit e774d5f1bc
11 changed files with 149 additions and 139 deletions
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36
tools/perf/trace/beauty/include/uapi/linux/prctl.h
View File

@@ -397,30 +397,24 @@ struct prctl_mm_map {
# define PR_RSEQ_SLICE_EXT_ENABLE 0x01
/*
* Get the current indirect branch tracking configuration for the current
* thread, this will be the value configured via PR_SET_INDIR_BR_LP_STATUS.
* Get or set the control flow integrity (CFI) configuration for the
* current thread.
*
* Some per-thread control flow integrity settings are not yet
* controlled through this prctl(); see for example
* PR_{GET,SET,LOCK}_SHADOW_STACK_STATUS
*/
#define PR_GET_INDIR_BR_LP_STATUS 80
#define PR_GET_CFI 80
#define PR_SET_CFI 81
/*
* Set the indirect branch tracking configuration. PR_INDIR_BR_LP_ENABLE will
* enable cpu feature for user thread, to track all indirect branches and ensure
* they land on arch defined landing pad instruction.
* x86 - If enabled, an indirect branch must land on an ENDBRANCH instruction.
* arch64 - If enabled, an indirect branch must land on a BTI instruction.
* riscv - If enabled, an indirect branch must land on an lpad instruction.
* PR_INDIR_BR_LP_DISABLE will disable feature for user thread and indirect
* branches will no more be tracked by cpu to land on arch defined landing pad
* instruction.
* Forward-edge CFI variants (excluding ARM64 BTI, which has its own
* prctl()s).
*/
#define PR_SET_INDIR_BR_LP_STATUS 81
# define PR_INDIR_BR_LP_ENABLE (1UL << 0)
#define PR_CFI_BRANCH_LANDING_PADS 0
/* Return and control values for PR_{GET,SET}_CFI */
# define PR_CFI_ENABLE _BITUL(0)
# define PR_CFI_DISABLE _BITUL(1)
# define PR_CFI_LOCK _BITUL(2)
/*
* Prevent further changes to the specified indirect branch tracking
* configuration. All bits may be locked via this call, including
* undefined bits.
*/
#define PR_LOCK_INDIR_BR_LP_STATUS 82
#endif /* _LINUX_PRCTL_H */

13
tools/testing/selftests/riscv/cfi/cfitests.c
View File

@@ -94,9 +94,9 @@ bool cfi_ptrace_test(void)
}
switch (ptrace_test_num) {
#define CFI_ENABLE_MASK (PTRACE_CFI_LP_EN_STATE | \
PTRACE_CFI_SS_EN_STATE | \
PTRACE_CFI_SS_PTR_STATE)
#define CFI_ENABLE_MASK (PTRACE_CFI_BRANCH_LANDING_PAD_EN_STATE | \
PTRACE_CFI_SHADOW_STACK_EN_STATE | \
PTRACE_CFI_SHADOW_STACK_PTR_STATE)
case 0:
if ((cfi_reg.cfi_status.cfi_state & CFI_ENABLE_MASK) != CFI_ENABLE_MASK)
ksft_exit_fail_msg("%s: ptrace_getregset failed, %llu\n", __func__,
@@ -106,7 +106,8 @@ bool cfi_ptrace_test(void)
__func__);
break;
case 1:
if (!(cfi_reg.cfi_status.cfi_state & PTRACE_CFI_ELP_STATE))
if (!(cfi_reg.cfi_status.cfi_state &
PTRACE_CFI_BRANCH_EXPECTED_LANDING_PAD_STATE))
ksft_exit_fail_msg("%s: elp must have been set\n", __func__);
/* clear elp state. not interested in anything else */
cfi_reg.cfi_status.cfi_state = 0;
@@ -145,11 +146,11 @@ int main(int argc, char *argv[])
* pads for user mode except lighting up a bit in senvcfg via a prctl.
* Enable landing pad support throughout the execution of the test binary.
*/
ret = my_syscall5(__NR_prctl, PR_GET_INDIR_BR_LP_STATUS, &lpad_status, 0, 0, 0);
ret = my_syscall5(__NR_prctl, PR_GET_CFI, PR_CFI_BRANCH_LANDING_PADS, &lpad_status, 0, 0);
if (ret)
ksft_exit_fail_msg("Get landing pad status failed with %d\n", ret);
if (!(lpad_status & PR_INDIR_BR_LP_ENABLE))
if (!(lpad_status & PR_CFI_ENABLE))
ksft_exit_fail_msg("Landing pad is not enabled, should be enabled via glibc\n");
ret = my_syscall5(__NR_prctl, PR_GET_SHADOW_STACK_STATUS, &ss_status, 0, 0, 0);