Merge tag 'objtool-urgent-2025-04-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull objtool fixes from Ingo Molnar:
 "These are objtool fixes and updates by Josh Poimboeuf, centered around
  the fallout from the new CONFIG_OBJTOOL_WERROR=y feature, which,
  despite its default-off nature, increased the profile/impact of
  objtool warnings:

   - Improve error handling and the presentation of warnings/errors

   - Revert the new summary warning line that some test-bot tools
     interpreted as new regressions

   - Fix a number of objtool warnings in various drivers, core kernel
     code and architecture code. About half of them are potential
     problems related to out-of-bounds accesses or potential undefined
     behavior, the other half are additional objtool annotations

   - Update objtool to latest (known) compiler quirks and objtool bugs
     triggered by compiler code generation

   - Misc fixes"

* tag 'objtool-urgent-2025-04-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (36 commits)
  objtool/loongarch: Add unwind hints in prepare_frametrace()
  rcu-tasks: Always inline rcu_irq_work_resched()
  context_tracking: Always inline ct_{nmi,irq}_{enter,exit}()
  sched/smt: Always inline sched_smt_active()
  objtool: Fix verbose disassembly if CROSS_COMPILE isn't set
  objtool: Change "warning:" to "error: " for fatal errors
  objtool: Always fail on fatal errors
  Revert "objtool: Increase per-function WARN_FUNC() rate limit"
  objtool: Append "()" to function name in "unexpected end of section" warning
  objtool: Ignore end-of-section jumps for KCOV/GCOV
  objtool: Silence more KCOV warnings, part 2
  objtool, drm/vmwgfx: Don't ignore vmw_send_msg() for ORC
  objtool: Fix STACK_FRAME_NON_STANDARD for cold subfunctions
  objtool: Fix segfault in ignore_unreachable_insn()
  objtool: Fix NULL printf() '%s' argument in builtin-check.c:save_argv()
  objtool, lkdtm: Obfuscate the do_nothing() pointer
  objtool, regulator: rk808: Remove potential undefined behavior in rk806_set_mode_dcdc()
  objtool, ASoC: codecs: wcd934x: Remove potential undefined behavior in wcd934x_slim_irq_handler()
  objtool, Input: cyapa - Remove undefined behavior in cyapa_update_fw_store()
  objtool, panic: Disable SMAP in __stack_chk_fail()
  ...

1 files changed, 11 insertions, 3 deletions

diff --git a/drivers/misc/lkdtm/perms.c b/drivers/misc/lkdtm/perms.c
index 5b861dbff27e..6c24426104ba 100644
--- a/drivers/misc/lkdtm/perms.c
+++ b/drivers/misc/lkdtm/perms.c
@@ -29,6 +29,13 @@ static const unsigned long rodata = 0xAA55AA55;
 static unsigned long ro_after_init __ro_after_init = 0x55AA5500;
 
 /*
+ * This is a pointer to do_nothing() which is initialized at runtime rather
+ * than build time to avoid objtool IBT validation warnings caused by an
+ * inlined unrolled memcpy() in execute_location().
+ */
+static void __ro_after_init *do_nothing_ptr;
+
+/*
  * This just returns to the caller. It is designed to be copied into
  * non-executable memory regions.
  */
@@ -65,13 +72,12 @@ static noinline __nocfi void execute_location(void *dst, bool write)
 {
 	void (*func)(void);
 	func_desc_t fdesc;
-	void *do_nothing_text = dereference_function_descriptor(do_nothing);
 
-	pr_info("attempting ok execution at %px\n", do_nothing_text);
+	pr_info("attempting ok execution at %px\n", do_nothing_ptr);
 	do_nothing();
 
 	if (write == CODE_WRITE) {
-		memcpy(dst, do_nothing_text, EXEC_SIZE);
+		memcpy(dst, do_nothing_ptr, EXEC_SIZE);
 		flush_icache_range((unsigned long)dst,
 				   (unsigned long)dst + EXEC_SIZE);
 	}
@@ -267,6 +273,8 @@ static void lkdtm_ACCESS_NULL(void)
 
 void __init lkdtm_perms_init(void)
 {
+	do_nothing_ptr = dereference_function_descriptor(do_nothing);
+
 	/* Make sure we can write to __ro_after_init values during __init */
 	ro_after_init |= 0xAA;
 }