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[PATCH 19/36] objtool/idle: Validate __cpuidle code as noinstr



Idle code is very like entry code in that RCU isn't available. As
such, add a little validation.

Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
---
 arch/alpha/kernel/vmlinux.lds.S      |    1 -
 arch/arc/kernel/vmlinux.lds.S        |    1 -
 arch/arm/include/asm/vmlinux.lds.h   |    1 -
 arch/arm64/kernel/vmlinux.lds.S      |    1 -
 arch/csky/kernel/vmlinux.lds.S       |    1 -
 arch/hexagon/kernel/vmlinux.lds.S    |    1 -
 arch/ia64/kernel/vmlinux.lds.S       |    1 -
 arch/loongarch/kernel/vmlinux.lds.S  |    1 -
 arch/m68k/kernel/vmlinux-nommu.lds   |    1 -
 arch/m68k/kernel/vmlinux-std.lds     |    1 -
 arch/m68k/kernel/vmlinux-sun3.lds    |    1 -
 arch/microblaze/kernel/vmlinux.lds.S |    1 -
 arch/mips/kernel/vmlinux.lds.S       |    1 -
 arch/nios2/kernel/vmlinux.lds.S      |    1 -
 arch/openrisc/kernel/vmlinux.lds.S   |    1 -
 arch/parisc/kernel/vmlinux.lds.S     |    1 -
 arch/powerpc/kernel/vmlinux.lds.S    |    1 -
 arch/riscv/kernel/vmlinux-xip.lds.S  |    1 -
 arch/riscv/kernel/vmlinux.lds.S      |    1 -
 arch/s390/kernel/vmlinux.lds.S       |    1 -
 arch/sh/kernel/vmlinux.lds.S         |    1 -
 arch/sparc/kernel/vmlinux.lds.S      |    1 -
 arch/um/kernel/dyn.lds.S             |    1 -
 arch/um/kernel/uml.lds.S             |    1 -
 arch/x86/include/asm/irqflags.h      |   11 ++++-------
 arch/x86/include/asm/mwait.h         |    2 +-
 arch/x86/kernel/vmlinux.lds.S        |    1 -
 arch/xtensa/kernel/vmlinux.lds.S     |    1 -
 include/asm-generic/vmlinux.lds.h    |    9 +++------
 include/linux/compiler_types.h       |    8 ++++++--
 include/linux/cpu.h                  |    3 ---
 kernel/module/main.c                 |    2 ++
 kernel/sched/idle.c                  |   15 +++++++++++++--
 tools/objtool/check.c                |   15 ++++++++++++++-
 34 files changed, 43 insertions(+), 48 deletions(-)

--- a/arch/alpha/kernel/vmlinux.lds.S
+++ b/arch/alpha/kernel/vmlinux.lds.S
@@ -27,7 +27,6 @@ SECTIONS
                HEAD_TEXT
                TEXT_TEXT
                SCHED_TEXT
-               CPUIDLE_TEXT
                LOCK_TEXT
                *(.fixup)
                *(.gnu.warning)
--- a/arch/arc/kernel/vmlinux.lds.S
+++ b/arch/arc/kernel/vmlinux.lds.S
@@ -85,7 +85,6 @@ SECTIONS
                _stext = .;
                TEXT_TEXT
                SCHED_TEXT
-               CPUIDLE_TEXT
                LOCK_TEXT
                KPROBES_TEXT
                IRQENTRY_TEXT
--- a/arch/arm/include/asm/vmlinux.lds.h
+++ b/arch/arm/include/asm/vmlinux.lds.h
@@ -96,7 +96,6 @@
                SOFTIRQENTRY_TEXT                                       \
                TEXT_TEXT                                               \
                SCHED_TEXT                                              \
-               CPUIDLE_TEXT                                            \
                LOCK_TEXT                                               \
                KPROBES_TEXT                                            \
                ARM_STUBS_TEXT                                          \
--- a/arch/arm64/kernel/vmlinux.lds.S
+++ b/arch/arm64/kernel/vmlinux.lds.S
@@ -163,7 +163,6 @@ SECTIONS
                        ENTRY_TEXT
                        TEXT_TEXT
                        SCHED_TEXT
-                       CPUIDLE_TEXT
                        LOCK_TEXT
                        KPROBES_TEXT
                        HYPERVISOR_TEXT
--- a/arch/csky/kernel/vmlinux.lds.S
+++ b/arch/csky/kernel/vmlinux.lds.S
@@ -38,7 +38,6 @@ SECTIONS
                SOFTIRQENTRY_TEXT
                TEXT_TEXT
                SCHED_TEXT
-               CPUIDLE_TEXT
                LOCK_TEXT
                KPROBES_TEXT
                *(.fixup)
--- a/arch/hexagon/kernel/vmlinux.lds.S
+++ b/arch/hexagon/kernel/vmlinux.lds.S
@@ -41,7 +41,6 @@ SECTIONS
                IRQENTRY_TEXT
                SOFTIRQENTRY_TEXT
                SCHED_TEXT
-               CPUIDLE_TEXT
                LOCK_TEXT
                KPROBES_TEXT
                *(.fixup)
--- a/arch/ia64/kernel/vmlinux.lds.S
+++ b/arch/ia64/kernel/vmlinux.lds.S
@@ -51,7 +51,6 @@ SECTIONS {
                __end_ivt_text = .;
                TEXT_TEXT
                SCHED_TEXT
-               CPUIDLE_TEXT
                LOCK_TEXT
                KPROBES_TEXT
                IRQENTRY_TEXT
--- a/arch/loongarch/kernel/vmlinux.lds.S
+++ b/arch/loongarch/kernel/vmlinux.lds.S
@@ -40,7 +40,6 @@ SECTIONS
        .text : {
                TEXT_TEXT
                SCHED_TEXT
-               CPUIDLE_TEXT
                LOCK_TEXT
                KPROBES_TEXT
                IRQENTRY_TEXT
--- a/arch/m68k/kernel/vmlinux-nommu.lds
+++ b/arch/m68k/kernel/vmlinux-nommu.lds
@@ -48,7 +48,6 @@ SECTIONS {
                IRQENTRY_TEXT
                SOFTIRQENTRY_TEXT
                SCHED_TEXT
-               CPUIDLE_TEXT
                LOCK_TEXT
                *(.fixup)
                . = ALIGN(16);
--- a/arch/m68k/kernel/vmlinux-std.lds
+++ b/arch/m68k/kernel/vmlinux-std.lds
@@ -19,7 +19,6 @@ SECTIONS
        IRQENTRY_TEXT
        SOFTIRQENTRY_TEXT
        SCHED_TEXT
-       CPUIDLE_TEXT
        LOCK_TEXT
        *(.fixup)
        *(.gnu.warning)
--- a/arch/m68k/kernel/vmlinux-sun3.lds
+++ b/arch/m68k/kernel/vmlinux-sun3.lds
@@ -19,7 +19,6 @@ SECTIONS
        IRQENTRY_TEXT
        SOFTIRQENTRY_TEXT
        SCHED_TEXT
-       CPUIDLE_TEXT
        LOCK_TEXT
        *(.fixup)
        *(.gnu.warning)
--- a/arch/microblaze/kernel/vmlinux.lds.S
+++ b/arch/microblaze/kernel/vmlinux.lds.S
@@ -36,7 +36,6 @@ SECTIONS {
                EXIT_TEXT
                EXIT_CALL
                SCHED_TEXT
-               CPUIDLE_TEXT
                LOCK_TEXT
                KPROBES_TEXT
                IRQENTRY_TEXT
--- a/arch/mips/kernel/vmlinux.lds.S
+++ b/arch/mips/kernel/vmlinux.lds.S
@@ -61,7 +61,6 @@ SECTIONS
        .text : {
                TEXT_TEXT
                SCHED_TEXT
-               CPUIDLE_TEXT
                LOCK_TEXT
                KPROBES_TEXT
                IRQENTRY_TEXT
--- a/arch/nios2/kernel/vmlinux.lds.S
+++ b/arch/nios2/kernel/vmlinux.lds.S
@@ -24,7 +24,6 @@ SECTIONS
        .text : {
                TEXT_TEXT
                SCHED_TEXT
-               CPUIDLE_TEXT
                LOCK_TEXT
                IRQENTRY_TEXT
                SOFTIRQENTRY_TEXT
--- a/arch/openrisc/kernel/vmlinux.lds.S
+++ b/arch/openrisc/kernel/vmlinux.lds.S
@@ -52,7 +52,6 @@ SECTIONS
           _stext = .;
          TEXT_TEXT
          SCHED_TEXT
-         CPUIDLE_TEXT
          LOCK_TEXT
          KPROBES_TEXT
          IRQENTRY_TEXT
--- a/arch/parisc/kernel/vmlinux.lds.S
+++ b/arch/parisc/kernel/vmlinux.lds.S
@@ -86,7 +86,6 @@ SECTIONS
                TEXT_TEXT
                LOCK_TEXT
                SCHED_TEXT
-               CPUIDLE_TEXT
                KPROBES_TEXT
                IRQENTRY_TEXT
                SOFTIRQENTRY_TEXT
--- a/arch/powerpc/kernel/vmlinux.lds.S
+++ b/arch/powerpc/kernel/vmlinux.lds.S
@@ -107,7 +107,6 @@ SECTIONS
 #endif
                NOINSTR_TEXT
                SCHED_TEXT
-               CPUIDLE_TEXT
                LOCK_TEXT
                KPROBES_TEXT
                IRQENTRY_TEXT
--- a/arch/riscv/kernel/vmlinux-xip.lds.S
+++ b/arch/riscv/kernel/vmlinux-xip.lds.S
@@ -39,7 +39,6 @@ SECTIONS
                _stext = .;
                TEXT_TEXT
                SCHED_TEXT
-               CPUIDLE_TEXT
                LOCK_TEXT
                KPROBES_TEXT
                ENTRY_TEXT
--- a/arch/riscv/kernel/vmlinux.lds.S
+++ b/arch/riscv/kernel/vmlinux.lds.S
@@ -42,7 +42,6 @@ SECTIONS
                _stext = .;
                TEXT_TEXT
                SCHED_TEXT
-               CPUIDLE_TEXT
                LOCK_TEXT
                KPROBES_TEXT
                ENTRY_TEXT
--- a/arch/s390/kernel/vmlinux.lds.S
+++ b/arch/s390/kernel/vmlinux.lds.S
@@ -42,7 +42,6 @@ SECTIONS
                HEAD_TEXT
                TEXT_TEXT
                SCHED_TEXT
-               CPUIDLE_TEXT
                LOCK_TEXT
                KPROBES_TEXT
                IRQENTRY_TEXT
--- a/arch/sh/kernel/vmlinux.lds.S
+++ b/arch/sh/kernel/vmlinux.lds.S
@@ -29,7 +29,6 @@ SECTIONS
                HEAD_TEXT
                TEXT_TEXT
                SCHED_TEXT
-               CPUIDLE_TEXT
                LOCK_TEXT
                KPROBES_TEXT
                IRQENTRY_TEXT
--- a/arch/sparc/kernel/vmlinux.lds.S
+++ b/arch/sparc/kernel/vmlinux.lds.S
@@ -50,7 +50,6 @@ SECTIONS
                HEAD_TEXT
                TEXT_TEXT
                SCHED_TEXT
-               CPUIDLE_TEXT
                LOCK_TEXT
                KPROBES_TEXT
                IRQENTRY_TEXT
--- a/arch/um/kernel/dyn.lds.S
+++ b/arch/um/kernel/dyn.lds.S
@@ -74,7 +74,6 @@ SECTIONS
     _stext = .;
     TEXT_TEXT
     SCHED_TEXT
-    CPUIDLE_TEXT
     LOCK_TEXT
     IRQENTRY_TEXT
     SOFTIRQENTRY_TEXT
--- a/arch/um/kernel/uml.lds.S
+++ b/arch/um/kernel/uml.lds.S
@@ -35,7 +35,6 @@ SECTIONS
     _stext = .;
     TEXT_TEXT
     SCHED_TEXT
-    CPUIDLE_TEXT
     LOCK_TEXT
     IRQENTRY_TEXT
     SOFTIRQENTRY_TEXT
--- a/arch/x86/include/asm/irqflags.h
+++ b/arch/x86/include/asm/irqflags.h
@@ -8,9 +8,6 @@
 
 #include <asm/nospec-branch.h>
 
-/* Provide __cpuidle; we can't safely include <linux/cpu.h> */
-#define __cpuidle __section(".cpuidle.text")
-
 /*
  * Interrupt control:
  */
@@ -45,13 +42,13 @@ static __always_inline void native_irq_e
        asm volatile("sti": : :"memory");
 }
 
-static inline __cpuidle void native_safe_halt(void)
+static __always_inline void native_safe_halt(void)
 {
        mds_idle_clear_cpu_buffers();
        asm volatile("sti; hlt": : :"memory");
 }
 
-static inline __cpuidle void native_halt(void)
+static __always_inline void native_halt(void)
 {
        mds_idle_clear_cpu_buffers();
        asm volatile("hlt": : :"memory");
@@ -84,7 +81,7 @@ static __always_inline void arch_local_i
  * Used in the idle loop; sti takes one instruction cycle
  * to complete:
  */
-static inline __cpuidle void arch_safe_halt(void)
+static __always_inline void arch_safe_halt(void)
 {
        native_safe_halt();
 }
@@ -93,7 +90,7 @@ static inline __cpuidle void arch_safe_h
  * Used when interrupts are already enabled or to
  * shutdown the processor:
  */
-static inline __cpuidle void halt(void)
+static __always_inline void halt(void)
 {
        native_halt();
 }
--- a/arch/x86/include/asm/mwait.h
+++ b/arch/x86/include/asm/mwait.h
@@ -104,7 +104,7 @@ static inline void __sti_mwait(unsigned
  * New with Core Duo processors, MWAIT can take some hints based on CPU
  * capability.
  */
-static inline void mwait_idle_with_hints(unsigned long eax, unsigned long ecx)
+static __always_inline void mwait_idle_with_hints(unsigned long eax, unsigned 
long ecx)
 {
        if (static_cpu_has_bug(X86_BUG_MONITOR) || 
!current_set_polling_and_test()) {
                if (static_cpu_has_bug(X86_BUG_CLFLUSH_MONITOR)) {
--- a/arch/x86/kernel/vmlinux.lds.S
+++ b/arch/x86/kernel/vmlinux.lds.S
@@ -129,7 +129,6 @@ SECTIONS
                HEAD_TEXT
                TEXT_TEXT
                SCHED_TEXT
-               CPUIDLE_TEXT
                LOCK_TEXT
                KPROBES_TEXT
                ALIGN_ENTRY_TEXT_BEGIN
--- a/arch/xtensa/kernel/vmlinux.lds.S
+++ b/arch/xtensa/kernel/vmlinux.lds.S
@@ -125,7 +125,6 @@ SECTIONS
     ENTRY_TEXT
     TEXT_TEXT
     SCHED_TEXT
-    CPUIDLE_TEXT
     LOCK_TEXT
     *(.fixup)
   }
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -559,6 +559,9 @@
                ALIGN_FUNCTION();                                       \
                __noinstr_text_start = .;                               \
                *(.noinstr.text)                                        \
+               __cpuidle_text_start = .;                               \
+               *(.cpuidle.text)                                        \
+               __cpuidle_text_end = .;                                 \
                __noinstr_text_end = .;
 
 /*
@@ -600,12 +603,6 @@
                *(.spinlock.text)                                       \
                __lock_text_end = .;
 
-#define CPUIDLE_TEXT                                                   \
-               ALIGN_FUNCTION();                                       \
-               __cpuidle_text_start = .;                               \
-               *(.cpuidle.text)                                        \
-               __cpuidle_text_end = .;
-
 #define KPROBES_TEXT                                                   \
                ALIGN_FUNCTION();                                       \
                __kprobes_text_start = .;                               \
--- a/include/linux/compiler_types.h
+++ b/include/linux/compiler_types.h
@@ -225,10 +225,14 @@ struct ftrace_likely_data {
 #endif
 
 /* Section for code which can't be instrumented at all */
-#define noinstr                                                                
\
-       noinline notrace __attribute((__section__(".noinstr.text")))    \
+#define __noinstr_section(section)                                     \
+       noinline notrace __attribute((__section__(section)))            \
        __no_kcsan __no_sanitize_address __no_profile __no_sanitize_coverage
 
+#define noinstr __noinstr_section(".noinstr.text")
+
+#define __cpuidle __noinstr_section(".cpuidle.text")
+
 #endif /* __KERNEL__ */
 
 #endif /* __ASSEMBLY__ */
--- a/include/linux/cpu.h
+++ b/include/linux/cpu.h
@@ -171,9 +171,6 @@ void __noreturn cpu_startup_entry(enum c
 
 void cpu_idle_poll_ctrl(bool enable);
 
-/* Attach to any functions which should be considered cpuidle. */
-#define __cpuidle      __section(".cpuidle.text")
-
 bool cpu_in_idle(unsigned long pc);
 
 void arch_cpu_idle(void);
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -376,7 +376,8 @@ static int decode_instructions(struct ob
                        sec->text = true;
 
                if (!strcmp(sec->name, ".noinstr.text") ||
-                   !strcmp(sec->name, ".entry.text"))
+                   !strcmp(sec->name, ".entry.text") ||
+                   !strcmp(sec->name, ".cpuidle.text"))
                        sec->noinstr = true;
 
                for (offset = 0; offset < sec->sh.sh_size; offset += insn->len) 
{
@@ -3080,6 +3081,12 @@ static inline bool noinstr_call_dest(str
                return true;
 
        /*
+        * If the symbol is a static_call trampoline, we can't tell.
+        */
+       if (func->static_call_tramp)
+               return true;
+
+       /*
         * The __ubsan_handle_*() calls are like WARN(), they only happen when
         * something 'BAD' happened. At the risk of taking the machine down,
         * let them proceed to get the message out.
@@ -3648,6 +3655,12 @@ static int validate_noinstr_sections(str
        if (sec) {
                warnings += validate_section(file, sec);
                warnings += validate_unwind_hints(file, sec);
+       }
+
+       sec = find_section_by_name(file->elf, ".cpuidle.text");
+       if (sec) {
+               warnings += validate_section(file, sec);
+               warnings += validate_unwind_hints(file, sec);
        }
 
        return warnings;





 


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