From 0372007f5a79d61d3cb48a507717b9afb5d6addd Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Wed, 4 Mar 2020 11:05:22 +0100 Subject: context_tracking: Ensure that the critical path cannot be instrumented context tracking lacks a few protection mechanisms against instrumentation: - While the core functions are marked NOKPROBE they lack protection against function tracing which is required as the function entry/exit points can be utilized by BPF. - static functions invoked from the protected functions need to be marked as well as they can be instrumented otherwise. - using plain inline allows the compiler to emit traceable and probable functions. Fix this by marking the functions noinstr and converting the plain inlines to __always_inline. The NOKPROBE_SYMBOL() annotations are removed as the .noinstr.text section is already excluded from being probed. Cures the following objtool warnings: vmlinux.o: warning: objtool: enter_from_user_mode()+0x34: call to __context_tracking_exit() leaves .noinstr.text section vmlinux.o: warning: objtool: prepare_exit_to_usermode()+0x29: call to __context_tracking_enter() leaves .noinstr.text section vmlinux.o: warning: objtool: syscall_return_slowpath()+0x29: call to __context_tracking_enter() leaves .noinstr.text section vmlinux.o: warning: objtool: do_syscall_64()+0x7f: call to __context_tracking_enter() leaves .noinstr.text section vmlinux.o: warning: objtool: do_int80_syscall_32()+0x3d: call to __context_tracking_enter() leaves .noinstr.text section vmlinux.o: warning: objtool: do_fast_syscall_32()+0x9c: call to __context_tracking_enter() leaves .noinstr.text section and generates new ones... Signed-off-by: Thomas Gleixner Reviewed-by: Masami Hiramatsu Reviewed-by: Alexandre Chartre Acked-by: Peter Zijlstra Link: https://lkml.kernel.org/r/20200505134340.811520478@linutronix.de --- include/linux/context_tracking.h | 6 +++--- include/linux/context_tracking_state.h | 6 +++--- 2 files changed, 6 insertions(+), 6 deletions(-) (limited to 'include') diff --git a/include/linux/context_tracking.h b/include/linux/context_tracking.h index 8cac62ee6add..981b880d5b60 100644 --- a/include/linux/context_tracking.h +++ b/include/linux/context_tracking.h @@ -33,13 +33,13 @@ static inline void user_exit(void) } /* Called with interrupts disabled. */ -static inline void user_enter_irqoff(void) +static __always_inline void user_enter_irqoff(void) { if (context_tracking_enabled()) __context_tracking_enter(CONTEXT_USER); } -static inline void user_exit_irqoff(void) +static __always_inline void user_exit_irqoff(void) { if (context_tracking_enabled()) __context_tracking_exit(CONTEXT_USER); @@ -75,7 +75,7 @@ static inline void exception_exit(enum ctx_state prev_ctx) * is enabled. If context tracking is disabled, returns * CONTEXT_DISABLED. This should be used primarily for debugging. */ -static inline enum ctx_state ct_state(void) +static __always_inline enum ctx_state ct_state(void) { return context_tracking_enabled() ? this_cpu_read(context_tracking.state) : CONTEXT_DISABLED; diff --git a/include/linux/context_tracking_state.h b/include/linux/context_tracking_state.h index e7fe6678b7ad..65a60d3313b0 100644 --- a/include/linux/context_tracking_state.h +++ b/include/linux/context_tracking_state.h @@ -26,12 +26,12 @@ struct context_tracking { extern struct static_key_false context_tracking_key; DECLARE_PER_CPU(struct context_tracking, context_tracking); -static inline bool context_tracking_enabled(void) +static __always_inline bool context_tracking_enabled(void) { return static_branch_unlikely(&context_tracking_key); } -static inline bool context_tracking_enabled_cpu(int cpu) +static __always_inline bool context_tracking_enabled_cpu(int cpu) { return context_tracking_enabled() && per_cpu(context_tracking.active, cpu); } @@ -41,7 +41,7 @@ static inline bool context_tracking_enabled_this_cpu(void) return context_tracking_enabled() && __this_cpu_read(context_tracking.active); } -static inline bool context_tracking_in_user(void) +static __always_inline bool context_tracking_in_user(void) { return __this_cpu_read(context_tracking.state) == CONTEXT_USER; } -- cgit v1.2.3 From 5916d5f9b3347344a3d96ba6b54cf8e290eba96a Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Fri, 13 Mar 2020 13:49:51 +0100 Subject: bug: Annotate WARN/BUG/stackfail as noinstr safe Warnings, bugs and stack protection fails from noinstr sections, e.g. low level and early entry code, are likely to be fatal. Mark them as "safe" to be invoked from noinstr protected code to avoid annotating all usage sites. Getting the information out is important. Signed-off-by: Thomas Gleixner Reviewed-by: Alexandre Chartre Acked-by: Peter Zijlstra Link: https://lkml.kernel.org/r/20200505134100.376598577@linutronix.de --- include/asm-generic/bug.h | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) (limited to 'include') diff --git a/include/asm-generic/bug.h b/include/asm-generic/bug.h index 384b5c835ced..c94e33ae3e7b 100644 --- a/include/asm-generic/bug.h +++ b/include/asm-generic/bug.h @@ -83,14 +83,19 @@ extern __printf(4, 5) void warn_slowpath_fmt(const char *file, const int line, unsigned taint, const char *fmt, ...); #define __WARN() __WARN_printf(TAINT_WARN, NULL) -#define __WARN_printf(taint, arg...) \ - warn_slowpath_fmt(__FILE__, __LINE__, taint, arg) +#define __WARN_printf(taint, arg...) do { \ + instrumentation_begin(); \ + warn_slowpath_fmt(__FILE__, __LINE__, taint, arg); \ + instrumentation_end(); \ + } while (0) #else extern __printf(1, 2) void __warn_printk(const char *fmt, ...); #define __WARN() __WARN_FLAGS(BUGFLAG_TAINT(TAINT_WARN)) #define __WARN_printf(taint, arg...) do { \ + instrumentation_begin(); \ __warn_printk(arg); \ __WARN_FLAGS(BUGFLAG_NO_CUT_HERE | BUGFLAG_TAINT(taint));\ + instrumentation_end(); \ } while (0) #define WARN_ON_ONCE(condition) ({ \ int __ret_warn_on = !!(condition); \ -- cgit v1.2.3 From df65bba1dcd8ffadd922a71196b78c6d7630c33b Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Wed, 19 Feb 2020 18:25:09 +0100 Subject: lib/bsearch: Provide __always_inline variant For code that needs the ultimate performance (it can inline the @cmp function too) or simply needs to avoid calling external functions for whatever reason, provide an __always_inline variant of bsearch(). [ tglx: Renamed to __inline_bsearch() as suggested by Andy ] Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Thomas Gleixner Reviewed-by: Alexandre Chartre Acked-by: Andy Lutomirski Link: https://lkml.kernel.org/r/20200505135313.624443814@linutronix.de --- include/linux/bsearch.h | 26 ++++++++++++++++++++++++-- 1 file changed, 24 insertions(+), 2 deletions(-) (limited to 'include') diff --git a/include/linux/bsearch.h b/include/linux/bsearch.h index 8ed53d7524ea..e66b711d091e 100644 --- a/include/linux/bsearch.h +++ b/include/linux/bsearch.h @@ -4,7 +4,29 @@ #include -void *bsearch(const void *key, const void *base, size_t num, size_t size, - cmp_func_t cmp); +static __always_inline +void *__inline_bsearch(const void *key, const void *base, size_t num, size_t size, cmp_func_t cmp) +{ + const char *pivot; + int result; + + while (num > 0) { + pivot = base + (num >> 1) * size; + result = cmp(key, pivot); + + if (result == 0) + return (void *)pivot; + + if (result > 0) { + base = pivot + size; + num--; + } + num >>= 1; + } + + return NULL; +} + +extern void *bsearch(const void *key, const void *base, size_t num, size_t size, cmp_func_t cmp); #endif /* _LINUX_BSEARCH_H */ -- cgit v1.2.3 From 2ab70319bc1f79228da4dce7b9d604740c9beeef Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Thu, 21 May 2020 22:05:14 +0200 Subject: nmi, tracing: Make hardware latency tracing noinstr safe The hardware latency tracer calls into instrumentable functions. Move the calls into the RCU watching sections and annotate them. Signed-off-by: Thomas Gleixner Signed-off-by: Ingo Molnar Acked-by: Andy Lutomirski Cc: Paul E. McKenney Link: https://lore.kernel.org/r/20200521202116.904176298@linutronix.de Signed-off-by: Ingo Molnar --- include/linux/hardirq.h | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) (limited to 'include') diff --git a/include/linux/hardirq.h b/include/linux/hardirq.h index e07cf853aa16..29b862aba740 100644 --- a/include/linux/hardirq.h +++ b/include/linux/hardirq.h @@ -87,20 +87,24 @@ extern void rcu_nmi_exit(void); arch_nmi_enter(); \ printk_nmi_enter(); \ lockdep_off(); \ - ftrace_nmi_enter(); \ BUG_ON(in_nmi() == NMI_MASK); \ __preempt_count_add(NMI_OFFSET + HARDIRQ_OFFSET); \ rcu_nmi_enter(); \ lockdep_hardirq_enter(); \ + instrumentation_begin(); \ + ftrace_nmi_enter(); \ + instrumentation_end(); \ } while (0) #define nmi_exit() \ do { \ + instrumentation_begin(); \ + ftrace_nmi_exit(); \ + instrumentation_end(); \ lockdep_hardirq_exit(); \ rcu_nmi_exit(); \ BUG_ON(!in_nmi()); \ __preempt_count_sub(NMI_OFFSET + HARDIRQ_OFFSET); \ - ftrace_nmi_exit(); \ lockdep_on(); \ printk_nmi_exit(); \ arch_nmi_exit(); \ -- cgit v1.2.3 From 8a6bc4787f05d087fda8e11ead225c8830250703 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Thu, 21 May 2020 22:05:21 +0200 Subject: genirq: Provide irq_enter/exit_rcu() irq_enter()/exit() currently include RCU handling. To properly separate the RCU handling code, provide variants which contain only the non-RCU related functionality. Signed-off-by: Thomas Gleixner Signed-off-by: Ingo Molnar Reviewed-by: Andy Lutomirski Link: https://lore.kernel.org/r/20200521202117.567023613@linutronix.de --- include/linux/hardirq.h | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) (limited to 'include') diff --git a/include/linux/hardirq.h b/include/linux/hardirq.h index 29b862aba740..3dc9102d16cf 100644 --- a/include/linux/hardirq.h +++ b/include/linux/hardirq.h @@ -40,7 +40,11 @@ static __always_inline void rcu_irq_enter_check_tick(void) /* * Enter irq context (on NO_HZ, update jiffies): */ -extern void irq_enter(void); +void irq_enter(void); +/* + * Like irq_enter(), but RCU is already watching. + */ +void irq_enter_rcu(void); /* * Exit irq context without processing softirqs: @@ -55,7 +59,12 @@ extern void irq_enter(void); /* * Exit irq context and process softirqs if needed: */ -extern void irq_exit(void); +void irq_exit(void); + +/* + * Like irq_exit(), but return with RCU watching. + */ +void irq_exit_rcu(void); #ifndef arch_nmi_enter #define arch_nmi_enter() do { } while (0) -- cgit v1.2.3 From 98a3bf195e1a14755da3d2b83e1dbb4a3158866d Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Thu, 21 May 2020 22:05:22 +0200 Subject: genirq: Provide __irq_enter/exit_raw() Like __irq_enter/exit() but without time accounting. To be used for "empty" system vectors like the scheduler IPI to avoid the overhead. Signed-off-by: Thomas Gleixner Signed-off-by: Ingo Molnar Reviewed-by: Andy Lutomirski Link: https://lore.kernel.org/r/20200521202117.671682341@linutronix.de --- include/linux/hardirq.h | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) (limited to 'include') diff --git a/include/linux/hardirq.h b/include/linux/hardirq.h index 3dc9102d16cf..03c9fece7d43 100644 --- a/include/linux/hardirq.h +++ b/include/linux/hardirq.h @@ -37,6 +37,17 @@ static __always_inline void rcu_irq_enter_check_tick(void) lockdep_hardirq_enter(); \ } while (0) +/* + * Like __irq_enter() without time accounting for fast + * interrupts, e.g. reschedule IPI where time accounting + * is more expensive than the actual interrupt. + */ +#define __irq_enter_raw() \ + do { \ + preempt_count_add(HARDIRQ_OFFSET); \ + lockdep_hardirq_enter(); \ + } while (0) + /* * Enter irq context (on NO_HZ, update jiffies): */ @@ -56,6 +67,15 @@ void irq_enter_rcu(void); preempt_count_sub(HARDIRQ_OFFSET); \ } while (0) +/* + * Like __irq_exit() without time accounting + */ +#define __irq_exit_raw() \ + do { \ + lockdep_hardirq_exit(); \ + preempt_count_sub(HARDIRQ_OFFSET); \ + } while (0) + /* * Exit irq context and process softirqs if needed: */ -- cgit v1.2.3 From 2f6474e4636bcc68af6c44abb2703f12d7f083da Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Thu, 21 May 2020 22:05:26 +0200 Subject: x86/entry: Switch XEN/PV hypercall entry to IDTENTRY Convert the XEN/PV hypercall to IDTENTRY: - Emit the ASM stub with DECLARE_IDTENTRY - Remove the ASM idtentry in 64-bit - Remove the open coded ASM entry code in 32-bit - Remove the old prototypes The handler stubs need to stay in ASM code as they need corner case handling and adjustment of the stack pointer. Provide a new C function which invokes the entry/exit handling and calls into the XEN handler on the interrupt stack if required. The exit code is slightly different from the regular idtentry_exit() on non-preemptible kernels. If the hypercall is preemptible and need_resched() is set then XEN provides a preempt hypercall scheduling function. Move this functionality into the entry code so it can use the existing idtentry functionality. [ mingo: Build fixes. ] Signed-off-by: Thomas Gleixner Signed-off-by: Ingo Molnar Acked-by: Andy Lutomirski Acked-by: Juergen Gross Tested-by: Juergen Gross Link: https://lore.kernel.org/r/20200521202118.055270078@linutronix.de --- include/xen/xen-ops.h | 19 +++++++------------ 1 file changed, 7 insertions(+), 12 deletions(-) (limited to 'include') diff --git a/include/xen/xen-ops.h b/include/xen/xen-ops.h index 095be1d66f31..39a5580f8feb 100644 --- a/include/xen/xen-ops.h +++ b/include/xen/xen-ops.h @@ -215,17 +215,7 @@ bool xen_running_on_version_or_later(unsigned int major, unsigned int minor); void xen_efi_runtime_setup(void); -#ifdef CONFIG_PREEMPTION - -static inline void xen_preemptible_hcall_begin(void) -{ -} - -static inline void xen_preemptible_hcall_end(void) -{ -} - -#else +#if defined(CONFIG_XEN_PV) && !defined(CONFIG_PREEMPTION) DECLARE_PER_CPU(bool, xen_in_preemptible_hcall); @@ -239,6 +229,11 @@ static inline void xen_preemptible_hcall_end(void) __this_cpu_write(xen_in_preemptible_hcall, false); } -#endif /* CONFIG_PREEMPTION */ +#else + +static inline void xen_preemptible_hcall_begin(void) { } +static inline void xen_preemptible_hcall_end(void) { } + +#endif /* CONFIG_XEN_PV && !CONFIG_PREEMPTION */ #endif /* INCLUDE_XEN_OPS_H */ -- cgit v1.2.3 From cb09ea2924cbf1a42da59bd30a59cc1836240bcb Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Thu, 21 May 2020 22:05:44 +0200 Subject: x86/entry: Convert XEN hypercall vector to IDTENTRY_SYSVEC Convert the last oldstyle defined vector to IDTENTRY_SYSVEC: - Implement the C entry point with DEFINE_IDTENTRY_SYSVEC - Emit the ASM stub with DECLARE_IDTENTRY_SYSVEC - Remove the ASM idtentries in 64-bit - Remove the BUILD_INTERRUPT entries in 32-bit - Remove the old prototypes Fixup the related XEN code by providing the primary C entry point in x86 to avoid cluttering the generic code with X86'isms. No functional change. Signed-off-by: Thomas Gleixner Signed-off-by: Ingo Molnar Acked-by: Andy Lutomirski Link: https://lore.kernel.org/r/20200521202119.741950104@linutronix.de --- include/xen/events.h | 7 ------- 1 file changed, 7 deletions(-) (limited to 'include') diff --git a/include/xen/events.h b/include/xen/events.h index 12b0dcb6a120..df1e6391f63f 100644 --- a/include/xen/events.h +++ b/include/xen/events.h @@ -90,13 +90,6 @@ unsigned int irq_from_evtchn(evtchn_port_t evtchn); int irq_from_virq(unsigned int cpu, unsigned int virq); evtchn_port_t evtchn_from_irq(unsigned irq); -#ifdef CONFIG_XEN_PVHVM -/* Xen HVM evtchn vector callback */ -void xen_hvm_callback_vector(void); -#ifdef CONFIG_TRACING -#define trace_xen_hvm_callback_vector xen_hvm_callback_vector -#endif -#endif int xen_set_callback_via(uint64_t via); void xen_evtchn_do_upcall(struct pt_regs *regs); void xen_hvm_evtchn_do_upcall(void); -- cgit v1.2.3 From 998c2034c6a36bd48284e8c8f945a6c6ffc0e3f0 Mon Sep 17 00:00:00 2001 From: Vitaly Kuznetsov Date: Wed, 20 May 2020 18:16:00 +0200 Subject: xen: Move xen_setup_callback_vector() definition to include/xen/hvm.h Kbuild test robot reports the following problem on ARM: for 'xen_setup_callback_vector' [-Wmissing-prototypes] 1664 | void xen_setup_callback_vector(void) {} | ^~~~~~~~~~~~~~~~~~~~~~~~~ The problem is that xen_setup_callback_vector is a x86 only thing, its definition is present in arch/x86/xen/xen-ops.h but not on ARM. In events_base.c there is a stub for !CONFIG_XEN_PVHVM but it is not declared as 'static'. On x86 the situation is hardly better: drivers/xen/events/events_base.c doesn't include 'xen-ops.h' from arch/x86/xen/, it includes its namesake from include/xen/ which also results in a 'no previous prototype' warning. Currently, xen_setup_callback_vector() has two call sites: one in drivers/xen/events_base.c and another in arch/x86/xen/suspend_hvm.c. The former is placed under #ifdef CONFIG_X86 and the later is only compiled in when CONFIG_XEN_PVHVM. Resolve the issue by moving xen_setup_callback_vector() declaration to arch neutral 'include/xen/hvm.h' as the implementation lives in arch neutral drivers/xen/events/events_base.c. Reported-by: kbuild test robot Signed-off-by: Vitaly Kuznetsov Signed-off-by: Thomas Gleixner Reviewed-by: Juergen Gross Link: https://lkml.kernel.org/r/20200520161600.361895-1-vkuznets@redhat.com --- include/xen/hvm.h | 2 ++ include/xen/interface/hvm/hvm_op.h | 2 ++ 2 files changed, 4 insertions(+) (limited to 'include') diff --git a/include/xen/hvm.h b/include/xen/hvm.h index 0b15f8cb17fc..b7fd7fc9ad41 100644 --- a/include/xen/hvm.h +++ b/include/xen/hvm.h @@ -58,4 +58,6 @@ static inline int hvm_get_parameter(int idx, uint64_t *value) #define HVM_CALLBACK_VECTOR(x) (((uint64_t)HVM_CALLBACK_VIA_TYPE_VECTOR)<<\ HVM_CALLBACK_VIA_TYPE_SHIFT | (x)) +void xen_setup_callback_vector(void); + #endif /* XEN_HVM_H__ */ diff --git a/include/xen/interface/hvm/hvm_op.h b/include/xen/interface/hvm/hvm_op.h index 956a04682865..25d945ef17de 100644 --- a/include/xen/interface/hvm/hvm_op.h +++ b/include/xen/interface/hvm/hvm_op.h @@ -21,6 +21,8 @@ #ifndef __XEN_PUBLIC_HVM_HVM_OP_H__ #define __XEN_PUBLIC_HVM_HVM_OP_H__ +#include + /* Get/set subcommands: the second argument of the hypercall is a * pointer to a xen_hvm_param struct. */ #define HVMOP_set_param 0 -- cgit v1.2.3 From bf2b3008440072068580c609d79a079656af0588 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 29 May 2020 23:27:40 +0200 Subject: x86/entry: Rename trace_hardirqs_off_prepare() The typical pattern for trace_hardirqs_off_prepare() is: ENTRY lockdep_hardirqs_off(); // because hardware ... do entry magic instrumentation_begin(); trace_hardirqs_off_prepare(); ... do actual work trace_hardirqs_on_prepare(); lockdep_hardirqs_on_prepare(); instrumentation_end(); ... do exit magic lockdep_hardirqs_on(); which shows that it's named wrong, rename it to trace_hardirqs_off_finish(), as it concludes the hardirq_off transition. Also, given that the above is the only correct order, make the traditional all-in-one trace_hardirqs_off() follow suit. Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Thomas Gleixner Link: https://lkml.kernel.org/r/20200529213321.415774872@infradead.org --- include/linux/irqflags.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'include') diff --git a/include/linux/irqflags.h b/include/linux/irqflags.h index d7f7e436c3af..6384d2813ded 100644 --- a/include/linux/irqflags.h +++ b/include/linux/irqflags.h @@ -32,7 +32,7 @@ #ifdef CONFIG_TRACE_IRQFLAGS extern void trace_hardirqs_on_prepare(void); - extern void trace_hardirqs_off_prepare(void); + extern void trace_hardirqs_off_finish(void); extern void trace_hardirqs_on(void); extern void trace_hardirqs_off(void); # define lockdep_hardirq_context(p) ((p)->hardirq_context) @@ -101,7 +101,7 @@ do { \ #else # define trace_hardirqs_on_prepare() do { } while (0) -# define trace_hardirqs_off_prepare() do { } while (0) +# define trace_hardirqs_off_finish() do { } while (0) # define trace_hardirqs_on() do { } while (0) # define trace_hardirqs_off() do { } while (0) # define lockdep_hardirq_context(p) 0 -- cgit v1.2.3 From 6eebad1ad303db360ebe3e51c2b9656c3d407157 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Wed, 3 Jun 2020 13:40:21 +0200 Subject: lockdep: __always_inline more for noinstr vmlinux.o: warning: objtool: debug_locks_off()+0xd: call to __debug_locks_off() leaves .noinstr.text section vmlinux.o: warning: objtool: match_held_lock()+0x6a: call to look_up_lock_class.isra.0() leaves .noinstr.text section vmlinux.o: warning: objtool: lock_is_held_type()+0x90: call to lockdep_recursion_finish() leaves .noinstr.text section Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Thomas Gleixner Link: https://lkml.kernel.org/r/20200603114052.185201076@infradead.org --- include/linux/debug_locks.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include') diff --git a/include/linux/debug_locks.h b/include/linux/debug_locks.h index 257ab3c92cb8..e7e45f0cc7da 100644 --- a/include/linux/debug_locks.h +++ b/include/linux/debug_locks.h @@ -12,7 +12,7 @@ extern int debug_locks __read_mostly; extern int debug_locks_silent __read_mostly; -static inline int __debug_locks_off(void) +static __always_inline int __debug_locks_off(void) { return xchg(&debug_locks, 0); } -- cgit v1.2.3 From f0178fc01fe46bab6a95415f5647d1a74efcad1b Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Wed, 10 Jun 2020 08:37:01 +0200 Subject: x86/entry: Unbreak __irqentry_text_start/end magic The entry rework moved interrupt entry code from the irqentry to the noinstr section which made the irqentry section empty. This breaks boundary checks which rely on the __irqentry_text_start/end markers to find out whether a function in a stack trace is interrupt/exception entry code. This affects the function graph tracer and filter_irq_stacks(). As the IDT entry points are all sequentialy emitted this is rather simple to unbreak by injecting __irqentry_text_start/end as global labels. To make this work correctly: - Remove the IRQENTRY_TEXT section from the x86 linker script - Define __irqentry so it breaks the build if it's used - Adjust the entry mirroring in PTI - Remove the redundant kprobes and unwinder bound checks Reported-by: Qian Cai Signed-off-by: Thomas Gleixner --- include/linux/interrupt.h | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) (limited to 'include') diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h index 80f637c3a6f3..5db970b6615a 100644 --- a/include/linux/interrupt.h +++ b/include/linux/interrupt.h @@ -760,8 +760,10 @@ extern int arch_early_irq_init(void); /* * We want to know which function is an entrypoint of a hardirq or a softirq. */ -#define __irq_entry __attribute__((__section__(".irqentry.text"))) -#define __softirq_entry \ - __attribute__((__section__(".softirqentry.text"))) +#ifndef __irq_entry +# define __irq_entry __attribute__((__section__(".irqentry.text"))) +#endif + +#define __softirq_entry __attribute__((__section__(".softirqentry.text"))) #endif -- cgit v1.2.3