On 21.08.2018 22:28, Nick Desaulniers wrote:
> Prefer _THIS_IP_ defined in linux/kernel.h.
>
> Most definitions of current_text_addr were the same as _THIS_IP_, but
> a few archs had inline assembly instead.
>
> This patch removes the final call site of current_text_addr, making all
> of the definitions dead code.
>
> Signed-off-by: Nick Desaulniers <ndesaulniers at google.com>
> ---
> I suspect that current_text_addr predated GNU C extensions for statement
> expressions and/or taking the address of a label, then the macro was
> reimplemented for every new archs include/asm/processor.h, even though
> there were very few call sites, and none required an assembly
> implementation vs the C implementation.
>
> I am sad to see a few neat arch specific ways of getting the ip/pc, but
> we should prefer the higher level C in cases where assembly is not
> required. And the definitions can always be found again in git history.
Currently alpha, s390, sparc, sh, c6x, ia64 and parisc provide an
inline assembly function to get the current instruction pointer.
As mentioned in an earlier thread, I personally would *prefer* if
_THIS_IP_ would use those inline assembly instructions on those
architectures instead of the (currently used) higher C-level
implementation.
Helge
> arch/alpha/include/asm/processor.h | 6 ------
> arch/arc/include/asm/processor.h | 8 --------
> arch/arm/include/asm/processor.h | 6 ------
> arch/arm64/include/asm/processor.h | 7 -------
> arch/c6x/include/asm/processor.h | 11 -----------
> arch/h8300/include/asm/processor.h | 6 ------
> arch/hexagon/include/asm/processor.h | 3 ---
> arch/ia64/include/asm/processor.h | 6 ------
> arch/m68k/include/asm/processor.h | 6 ------
> arch/microblaze/include/asm/processor.h | 12 ------------
> arch/mips/include/asm/processor.h | 5 -----
> arch/nds32/include/asm/processor.h | 6 ------
> arch/nios2/include/asm/processor.h | 6 ------
> arch/openrisc/include/asm/processor.h | 5 -----
> arch/parisc/include/asm/processor.h | 11 -----------
> arch/powerpc/include/asm/processor.h | 6 ------
> arch/riscv/include/asm/processor.h | 6 ------
> arch/s390/include/asm/processor.h | 6 ------
> arch/sh/include/asm/processor_32.h | 6 ------
> arch/sh/include/asm/processor_64.h | 15 ---------------
> arch/sparc/include/asm/processor_32.h | 6 ------
> arch/sparc/include/asm/processor_64.h | 6 ------
> arch/unicore32/include/asm/processor.h | 6 ------
> arch/x86/include/asm/kexec.h | 3 ++-
> arch/x86/include/asm/processor.h | 12 ------------
> arch/x86/um/asm/processor_32.h | 8 --------
> arch/x86/um/asm/processor_64.h | 3 ---
> arch/xtensa/include/asm/processor.h | 8 --------
> 28 files changed, 2 insertions(+), 193 deletions(-)
>
> diff --git a/arch/alpha/include/asm/processor.h b/arch/alpha/include/asm/processor.h
> index cb05d045efe3..6100431da07a 100644
> --- a/arch/alpha/include/asm/processor.h
> +++ b/arch/alpha/include/asm/processor.h
> @@ -10,12 +10,6 @@
>
> #include <linux/personality.h> /* for ADDR_LIMIT_32BIT */
>
> -/*
> - * Returns current instruction pointer ("program counter").
> - */
> -#define current_text_addr() \
> - ({ void *__pc; __asm__ ("br %0,.+4" : "=r"(__pc)); __pc; })
> -
> /*
> * We have a 42-bit user address space: 4TB user VM...
> */
> diff --git a/arch/arc/include/asm/processor.h b/arch/arc/include/asm/processor.h
> index 8ee41e988169..10346d6cf926 100644
> --- a/arch/arc/include/asm/processor.h
> +++ b/arch/arc/include/asm/processor.h
> @@ -98,14 +98,6 @@ extern void start_thread(struct pt_regs * regs, unsigned long pc,
>
> extern unsigned int get_wchan(struct task_struct *p);
>
> -/*
> - * Default implementation of macro that returns current
> - * instruction pointer ("program counter").
> - * Should the PC register be read instead ? This macro does not seem to
> - * be used in many places so this wont be all that bad.
> - */
> -#define current_text_addr() ({ __label__ _l; _l: &&_l; })
> -
> #endif /* !__ASSEMBLY__ */
>
> /*
> diff --git a/arch/arm/include/asm/processor.h b/arch/arm/include/asm/processor.h
> index 1bf65b47808a..120f4c9bbfde 100644
> --- a/arch/arm/include/asm/processor.h
> +++ b/arch/arm/include/asm/processor.h
> @@ -11,12 +11,6 @@
> #ifndef __ASM_ARM_PROCESSOR_H
> #define __ASM_ARM_PROCESSOR_H
>
> -/*
> - * Default implementation of macro that returns current
> - * instruction pointer ("program counter").
> - */
> -#define current_text_addr() ({ __label__ _l; _l: &&_l;})
> -
> #ifdef __KERNEL__
>
> #include <asm/hw_breakpoint.h>
> diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h
> index 79657ad91397..966214f473b4 100644
> --- a/arch/arm64/include/asm/processor.h
> +++ b/arch/arm64/include/asm/processor.h
> @@ -25,13 +25,6 @@
> #define USER_DS (TASK_SIZE_64 - 1)
>
> #ifndef __ASSEMBLY__
> -
> -/*
> - * Default implementation of macro that returns current
> - * instruction pointer ("program counter").
> - */
> -#define current_text_addr() ({ __label__ _l; _l: &&_l;})
> -
> #ifdef __KERNEL__
>
> #include <linux/build_bug.h>
> diff --git a/arch/c6x/include/asm/processor.h b/arch/c6x/include/asm/processor.h
> index 8f7cce829f8e..a8581f5b27f6 100644
> --- a/arch/c6x/include/asm/processor.h
> +++ b/arch/c6x/include/asm/processor.h
> @@ -17,17 +17,6 @@
> #include <asm/page.h>
> #include <asm/current.h>
>
> -/*
> - * Default implementation of macro that returns current
> - * instruction pointer ("program counter").
> - */
> -#define current_text_addr() \
> -({ \
> - void *__pc; \
> - asm("mvc .S2 pce1,%0\n" : "=b"(__pc)); \
> - __pc; \
> -})
> -
> /*
> * User space process size. This is mostly meaningless for NOMMU
> * but some C6X processors may have RAM addresses up to 0xFFFFFFFF.
> diff --git a/arch/h8300/include/asm/processor.h b/arch/h8300/include/asm/processor.h
> index 985346393e4a..a060b41b2d31 100644
> --- a/arch/h8300/include/asm/processor.h
> +++ b/arch/h8300/include/asm/processor.h
> @@ -12,12 +12,6 @@
> #ifndef __ASM_H8300_PROCESSOR_H
> #define __ASM_H8300_PROCESSOR_H
>
> -/*
> - * Default implementation of macro that returns current
> - * instruction pointer ("program counter").
> - */
> -#define current_text_addr() ({ __label__ _l; _l: &&_l; })
> -
> #include <linux/compiler.h>
> #include <asm/segment.h>
> #include <asm/ptrace.h>
> diff --git a/arch/hexagon/include/asm/processor.h b/arch/hexagon/include/asm/processor.h
> index ce67940860a5..227bcb9cfdac 100644
> --- a/arch/hexagon/include/asm/processor.h
> +++ b/arch/hexagon/include/asm/processor.h
> @@ -27,9 +27,6 @@
> #include <asm/registers.h>
> #include <asm/hexagon_vm.h>
>
> -/* must be a macro */
> -#define current_text_addr() ({ __label__ _l; _l: &&_l; })
> -
> /* task_struct, defined elsewhere, is the "process descriptor" */
> struct task_struct;
>
> diff --git a/arch/ia64/include/asm/processor.h b/arch/ia64/include/asm/processor.h
> index 10061ccf0440..c91ef98ed6bf 100644
> --- a/arch/ia64/include/asm/processor.h
> +++ b/arch/ia64/include/asm/processor.h
> @@ -602,12 +602,6 @@ ia64_set_unat (__u64 *unat, void *spill_addr, unsigned long nat)
> *unat = (*unat & ~mask) | (nat << bit);
> }
>
> -/*
> - * Get the current instruction/program counter value.
> - */
> -#define current_text_addr() \
> - ({ void *_pc; _pc = (void *)ia64_getreg(_IA64_REG_IP); _pc; })
> -
> static inline __u64
> ia64_get_ivr (void)
> {
> diff --git a/arch/m68k/include/asm/processor.h b/arch/m68k/include/asm/processor.h
> index 464e9f5f50ee..3750819ac5a1 100644
> --- a/arch/m68k/include/asm/processor.h
> +++ b/arch/m68k/include/asm/processor.h
> @@ -8,12 +8,6 @@
> #ifndef __ASM_M68K_PROCESSOR_H
> #define __ASM_M68K_PROCESSOR_H
>
> -/*
> - * Default implementation of macro that returns current
> - * instruction pointer ("program counter").
> - */
> -#define current_text_addr() ({ __label__ _l; _l: &&_l;})
> -
> #include <linux/thread_info.h>
> #include <asm/segment.h>
> #include <asm/fpu.h>
> diff --git a/arch/microblaze/include/asm/processor.h b/arch/microblaze/include/asm/processor.h
> index 330d556860ba..66b537b8d138 100644
> --- a/arch/microblaze/include/asm/processor.h
> +++ b/arch/microblaze/include/asm/processor.h
> @@ -45,12 +45,6 @@ extern void ret_from_kernel_thread(void);
> */
> # define TASK_SIZE (0x81000000 - 0x80000000)
>
> -/*
> - * Default implementation of macro that returns current
> - * instruction pointer ("program counter").
> - */
> -# define current_text_addr() ({ __label__ _l; _l: &&_l; })
> -
> /*
> * This decides where the kernel will search for a free chunk of vm
> * space during mmap's. We won't be using it
> @@ -92,12 +86,6 @@ extern unsigned long get_wchan(struct task_struct *p);
>
> # ifndef __ASSEMBLY__
>
> -/*
> - * Default implementation of macro that returns current
> - * instruction pointer ("program counter").
> - */
> -# define current_text_addr() ({ __label__ _l; _l: &&_l; })
> -
> /* If you change this, you must change the associated assembly-languages
> * constants defined below, THREAD_*.
> */
> diff --git a/arch/mips/include/asm/processor.h b/arch/mips/include/asm/processor.h
> index b2fa62922d88..f08417f8772e 100644
> --- a/arch/mips/include/asm/processor.h
> +++ b/arch/mips/include/asm/processor.h
> @@ -22,11 +22,6 @@
> #include <asm/mipsregs.h>
> #include <asm/prefetch.h>
>
> -/*
> - * Return current * instruction pointer ("program counter").
> - */
> -#define current_text_addr() ({ __label__ _l; _l: &&_l;})
> -
> /*
> * System setup and hardware flags..
> */
> diff --git a/arch/nds32/include/asm/processor.h b/arch/nds32/include/asm/processor.h
> index 9c83caf4269f..c2660f566bac 100644
> --- a/arch/nds32/include/asm/processor.h
> +++ b/arch/nds32/include/asm/processor.h
> @@ -4,12 +4,6 @@
> #ifndef __ASM_NDS32_PROCESSOR_H
> #define __ASM_NDS32_PROCESSOR_H
>
> -/*
> - * Default implementation of macro that returns current
> - * instruction pointer ("program counter").
> - */
> -#define current_text_addr() ({ __label__ _l; _l: &&_l;})
> -
> #ifdef __KERNEL__
>
> #include <asm/ptrace.h>
> diff --git a/arch/nios2/include/asm/processor.h b/arch/nios2/include/asm/processor.h
> index 4944e2e1d8b0..94bcb86f679f 100644
> --- a/arch/nios2/include/asm/processor.h
> +++ b/arch/nios2/include/asm/processor.h
> @@ -38,12 +38,6 @@
> #define KUSER_SIZE (PAGE_SIZE)
> #ifndef __ASSEMBLY__
>
> -/*
> - * Default implementation of macro that returns current
> - * instruction pointer ("program counter").
> - */
> -#define current_text_addr() ({ __label__ _l; _l: &&_l; })
> -
> # define TASK_SIZE 0x7FFF0000UL
> # define TASK_UNMAPPED_BASE (PAGE_ALIGN(TASK_SIZE / 3))
>
> diff --git a/arch/openrisc/include/asm/processor.h b/arch/openrisc/include/asm/processor.h
> index af31a9fe736a..351d3aed7a06 100644
> --- a/arch/openrisc/include/asm/processor.h
> +++ b/arch/openrisc/include/asm/processor.h
> @@ -30,11 +30,6 @@
> | SPR_SR_DCE | SPR_SR_SM)
> #define USER_SR (SPR_SR_DME | SPR_SR_IME | SPR_SR_ICE \
> | SPR_SR_DCE | SPR_SR_IEE | SPR_SR_TEE)
> -/*
> - * Default implementation of macro that returns current
> - * instruction pointer ("program counter").
> - */
> -#define current_text_addr() ({ __label__ _l; _l: &&_l; })
>
> /*
> * User space process size. This is hardcoded into a few places,
> diff --git a/arch/parisc/include/asm/processor.h b/arch/parisc/include/asm/processor.h
> index 2dbe5580a1a4..0d7f64ef9c7d 100644
> --- a/arch/parisc/include/asm/processor.h
> +++ b/arch/parisc/include/asm/processor.h
> @@ -20,17 +20,6 @@
> #include <asm/percpu.h>
> #endif /* __ASSEMBLY__ */
>
> -/*
> - * Default implementation of macro that returns current
> - * instruction pointer ("program counter").
> - */
> -#ifdef CONFIG_PA20
> -#define current_ia(x) __asm__("mfia %0" : "=r"(x))
> -#else /* mfia added in pa2.0 */
> -#define current_ia(x) __asm__("blr 0,%0\n\tnop" : "=r"(x))
> -#endif
> -#define current_text_addr() ({ void *pc; current_ia(pc); pc; })
> -
> #define HAVE_ARCH_PICK_MMAP_LAYOUT
>
> #define TASK_SIZE_OF(tsk) ((tsk)->thread.task_size)
> diff --git a/arch/powerpc/include/asm/processor.h b/arch/powerpc/include/asm/processor.h
> index 52fadded5c1e..1fff74df06e6 100644
> --- a/arch/powerpc/include/asm/processor.h
> +++ b/arch/powerpc/include/asm/processor.h
> @@ -67,12 +67,6 @@ extern int _chrp_type;
>
> #endif /* defined(__KERNEL__) && defined(CONFIG_PPC32) */
>
> -/*
> - * Default implementation of macro that returns current
> - * instruction pointer ("program counter").
> - */
> -#define current_text_addr() ({ __label__ _l; _l: &&_l;})
> -
> /* Macros for adjusting thread priority (hardware multi-threading) */
> #define HMT_very_low() asm volatile("or 31,31,31 # very low priority")
> #define HMT_low() asm volatile("or 1,1,1 # low priority")
> diff --git a/arch/riscv/include/asm/processor.h b/arch/riscv/include/asm/processor.h
> index 3fe4af8147d2..020e35947060 100644
> --- a/arch/riscv/include/asm/processor.h
> +++ b/arch/riscv/include/asm/processor.h
> @@ -33,12 +33,6 @@
> struct task_struct;
> struct pt_regs;
>
> -/*
> - * Default implementation of macro that returns current
> - * instruction pointer ("program counter").
> - */
> -#define current_text_addr() ({ __label__ _l; _l: &&_l; })
> -
> /* CPU-specific state of a task */
> struct thread_struct {
> /* Callee-saved registers */
> diff --git a/arch/s390/include/asm/processor.h b/arch/s390/include/asm/processor.h
> index 7f2953c15c37..f8028d37bb18 100644
> --- a/arch/s390/include/asm/processor.h
> +++ b/arch/s390/include/asm/processor.h
> @@ -73,12 +73,6 @@ static inline int test_cpu_flag_of(int flag, int cpu)
>
> #define arch_needs_cpu() test_cpu_flag(CIF_NOHZ_DELAY)
>
> -/*
> - * Default implementation of macro that returns current
> - * instruction pointer ("program counter").
> - */
> -#define current_text_addr() ({ void *pc; asm("basr %0,0" : "=a" (pc)); pc; })
> -
> static inline void get_cpu_id(struct cpuid *ptr)
> {
> asm volatile("stidp %0" : "=Q" (*ptr));
> diff --git a/arch/sh/include/asm/processor_32.h b/arch/sh/include/asm/processor_32.h
> index 95100d8a0b7b..0e0ecc0132e3 100644
> --- a/arch/sh/include/asm/processor_32.h
> +++ b/arch/sh/include/asm/processor_32.h
> @@ -16,12 +16,6 @@
> #include <asm/types.h>
> #include <asm/hw_breakpoint.h>
>
> -/*
> - * Default implementation of macro that returns current
> - * instruction pointer ("program counter").
> - */
> -#define current_text_addr() ({ void *pc; __asm__("mova 1f, %0\n.align 2\n1:":"=z" (pc)); pc; })
> -
> /* Core Processor Version Register */
> #define CCN_PVR 0xff000030
> #define CCN_CVR 0xff000040
> diff --git a/arch/sh/include/asm/processor_64.h b/arch/sh/include/asm/processor_64.h
> index 777a16318aff..f3d7075648d0 100644
> --- a/arch/sh/include/asm/processor_64.h
> +++ b/arch/sh/include/asm/processor_64.h
> @@ -19,21 +19,6 @@
> #include <asm/types.h>
> #include <cpu/registers.h>
>
> -/*
> - * Default implementation of macro that returns current
> - * instruction pointer ("program counter").
> - */
> -#define current_text_addr() ({ \
> -void *pc; \
> -unsigned long long __dummy = 0; \
> -__asm__("gettr tr0, %1\n\t" \
> - "pta 4, tr0\n\t" \
> - "gettr tr0, %0\n\t" \
> - "ptabs %1, tr0\n\t" \
> - :"=r" (pc), "=r" (__dummy) \
> - : "1" (__dummy)); \
> -pc; })
> -
> #endif
>
> /*
> diff --git a/arch/sparc/include/asm/processor_32.h b/arch/sparc/include/asm/processor_32.h
> index 192493c257fa..3c4bc2189092 100644
> --- a/arch/sparc/include/asm/processor_32.h
> +++ b/arch/sparc/include/asm/processor_32.h
> @@ -7,12 +7,6 @@
> #ifndef __ASM_SPARC_PROCESSOR_H
> #define __ASM_SPARC_PROCESSOR_H
>
> -/*
> - * Sparc32 implementation of macro that returns current
> - * instruction pointer ("program counter").
> - */
> -#define current_text_addr() ({ void *pc; __asm__("sethi %%hi(1f), %0; or %0, %%lo(1f), %0;\n1:" : "=r" (pc)); pc; })
> -
> #include <asm/psr.h>
> #include <asm/ptrace.h>
> #include <asm/head.h>
> diff --git a/arch/sparc/include/asm/processor_64.h b/arch/sparc/include/asm/processor_64.h
> index aac23d4a4ddd..5cf145f18f36 100644
> --- a/arch/sparc/include/asm/processor_64.h
> +++ b/arch/sparc/include/asm/processor_64.h
> @@ -8,12 +8,6 @@
> #ifndef __ASM_SPARC64_PROCESSOR_H
> #define __ASM_SPARC64_PROCESSOR_H
>
> -/*
> - * Sparc64 implementation of macro that returns current
> - * instruction pointer ("program counter").
> - */
> -#define current_text_addr() ({ void *pc; __asm__("rd %%pc, %0" : "=r" (pc)); pc; })
> -
> #include <asm/asi.h>
> #include <asm/pstate.h>
> #include <asm/ptrace.h>
> diff --git a/arch/unicore32/include/asm/processor.h b/arch/unicore32/include/asm/processor.h
> index 4eaa42167667..b772ed1c0f25 100644
> --- a/arch/unicore32/include/asm/processor.h
> +++ b/arch/unicore32/include/asm/processor.h
> @@ -13,12 +13,6 @@
> #ifndef __UNICORE_PROCESSOR_H__
> #define __UNICORE_PROCESSOR_H__
>
> -/*
> - * Default implementation of macro that returns current
> - * instruction pointer ("program counter").
> - */
> -#define current_text_addr() ({ __label__ _l; _l: &&_l; })
> -
> #ifdef __KERNEL__
>
> #include <asm/ptrace.h>
> diff --git a/arch/x86/include/asm/kexec.h b/arch/x86/include/asm/kexec.h
> index f327236f0fa7..86924d594ecd 100644
> --- a/arch/x86/include/asm/kexec.h
> +++ b/arch/x86/include/asm/kexec.h
> @@ -21,6 +21,7 @@
> #ifndef __ASSEMBLY__
>
> #include <linux/string.h>
> +#include <linux/kernel.h>
>
> #include <asm/page.h>
> #include <asm/ptrace.h>
> @@ -132,7 +133,7 @@ static inline void crash_setup_regs(struct pt_regs *newregs,
> asm volatile("movl %%cs, %%eax;" :"=a"(newregs->cs));
> asm volatile("pushfq; popq %0" :"=m"(newregs->flags));
> #endif
> - newregs->ip = (unsigned long)current_text_addr();
> + newregs->ip = _THIS_IP_;
> }
> }
>
> diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
> index 682286aca881..20080b303605 100644
> --- a/arch/x86/include/asm/processor.h
> +++ b/arch/x86/include/asm/processor.h
> @@ -42,18 +42,6 @@ struct vm86;
> #define NET_IP_ALIGN 0
>
> #define HBP_NUM 4
> -/*
> - * Default implementation of macro that returns current
> - * instruction pointer ("program counter").
> - */
> -static inline void *current_text_addr(void)
> -{
> - void *pc;
> -
> - asm volatile("mov $1f, %0; 1:":"=r" (pc));
> -
> - return pc;
> -}
>
> /*
> * These alignment constraints are for performance in the vSMP case,
> diff --git a/arch/x86/um/asm/processor_32.h b/arch/x86/um/asm/processor_32.h
> index c112de81c9e1..5fb1b8449adf 100644
> --- a/arch/x86/um/asm/processor_32.h
> +++ b/arch/x86/um/asm/processor_32.h
> @@ -47,14 +47,6 @@ static inline void arch_copy_thread(struct arch_thread *from,
> memcpy(&to->tls_array, &from->tls_array, sizeof(from->tls_array));
> }
>
> -/*
> - * Default implementation of macro that returns current
> - * instruction pointer ("program counter"). Stolen
> - * from asm-i386/processor.h
> - */
> -#define current_text_addr() \
> - ({ void *pc; __asm__("movl $1f,%0\n1:":"=g" (pc)); pc; })
> -
> #define current_sp() ({ void *sp; __asm__("movl %%esp, %0" : "=r" (sp) : ); sp; })
> #define current_bp() ({ unsigned long bp; __asm__("movl %%ebp, %0" : "=r" (bp) : ); bp; })
>
> diff --git a/arch/x86/um/asm/processor_64.h b/arch/x86/um/asm/processor_64.h
> index c3be85205a65..1ef9c21877bc 100644
> --- a/arch/x86/um/asm/processor_64.h
> +++ b/arch/x86/um/asm/processor_64.h
> @@ -31,9 +31,6 @@ static inline void arch_copy_thread(struct arch_thread *from,
> to->fs = from->fs;
> }
>
> -#define current_text_addr() \
> - ({ void *pc; __asm__("movq $1f,%0\n1:":"=g" (pc)); pc; })
> -
> #define current_sp() ({ void *sp; __asm__("movq %%rsp, %0" : "=r" (sp) : ); sp; })
> #define current_bp() ({ unsigned long bp; __asm__("movq %%rbp, %0" : "=r" (bp) : ); bp; })
>
> diff --git a/arch/xtensa/include/asm/processor.h b/arch/xtensa/include/asm/processor.h
> index 5b0027d4ecc0..68891c992105 100644
> --- a/arch/xtensa/include/asm/processor.h
> +++ b/arch/xtensa/include/asm/processor.h
> @@ -153,14 +153,6 @@ struct thread_struct {
> int align[0] __attribute__ ((aligned(16)));
> };
>
> -
> -/*
> - * Default implementation of macro that returns current
> - * instruction pointer ("program counter").
> - */
> -#define current_text_addr() ({ __label__ _l; _l: &&_l;})
> -
> -
> /* This decides where the kernel will search for a free chunk of vm
> * space during mmap's.
> */
>
