--- zzzz-none-000/linux-3.10.107/arch/arm/kernel/entry-common.S 2017-06-27 09:49:32.000000000 +0000 +++ scorpion-7490-727/linux-3.10.107/arch/arm/kernel/entry-common.S 2021-02-04 17:41:59.000000000 +0000 @@ -8,6 +8,7 @@ * published by the Free Software Foundation. */ +#include #include #include #include @@ -23,35 +24,55 @@ .align 5 +#if !(IS_ENABLED(CONFIG_TRACE_IRQFLAGS) || IS_ENABLED(CONFIG_CONTEXT_TRACKING)) /* - * This is the fast syscall return path. We do as little as - * possible here, and this includes saving r0 back into the SVC - * stack. + * This is the fast syscall return path. We do as little as possible here, + * such as avoiding writing r0 to the stack. We only use this path if we + * have tracing and context tracking disabled - the overheads from those + * features make this path too inefficient. */ ret_fast_syscall: UNWIND(.fnstart ) UNWIND(.cantunwind ) - disable_irq @ disable interrupts + disable_irq_notrace @ disable interrupts ldr r1, [tsk, #TI_FLAGS] @ re-check for syscall tracing - tst r1, #_TIF_SYSCALL_WORK - bne __sys_trace_return - tst r1, #_TIF_WORK_MASK + tst r1, #_TIF_SYSCALL_WORK | _TIF_WORK_MASK bne fast_work_pending - asm_trace_hardirqs_on /* perform architecture specific actions before user return */ arch_ret_to_user r1, lr - ct_user_enter restore_user_regs fast = 1, offset = S_OFF UNWIND(.fnend ) +ENDPROC(ret_fast_syscall) -/* - * Ok, we need to do extra processing, enter the slow path. - */ + /* Ok, we need to do extra processing, enter the slow path. */ fast_work_pending: str r0, [sp, #S_R0+S_OFF]! @ returned r0 -work_pending: + /* fall through to work_pending */ +#else +/* + * The "replacement" ret_fast_syscall for when tracing or context tracking + * is enabled. As we will need to call out to some C functions, we save + * r0 first to avoid needing to save registers around each C function call. + */ +ret_fast_syscall: + UNWIND(.fnstart ) + UNWIND(.cantunwind ) + str r0, [sp, #S_R0 + S_OFF]! @ save returned r0 + disable_irq_notrace @ disable interrupts + ldr r1, [tsk, #TI_FLAGS] @ re-check for syscall tracing + tst r1, #_TIF_SYSCALL_WORK | _TIF_WORK_MASK + beq no_work_pending + UNWIND(.fnend ) +ENDPROC(ret_fast_syscall) + + /* Slower path - fall through to work_pending */ +#endif + + tst r1, #_TIF_SYSCALL_WORK + bne __sys_trace_return_nosave +slow_work_pending: mov r0, sp @ 'regs' mov r2, why @ 'syscall' bl do_work_pending @@ -60,19 +81,23 @@ movlt scno, #(__NR_restart_syscall - __NR_SYSCALL_BASE) ldmia sp, {r0 - r6} @ have to reload r0 - r6 b local_restart @ ... and off we go +ENDPROC(ret_fast_syscall) /* * "slow" syscall return path. "why" tells us if this was a real syscall. + * IRQs may be enabled here, so always disable them. Note that we use the + * "notrace" version to avoid calling into the tracing code unnecessarily. + * do_work_pending() will update this state if necessary. */ ENTRY(ret_to_user) ret_slow_syscall: - disable_irq @ disable interrupts + disable_irq_notrace @ disable interrupts ENTRY(ret_to_user_from_irq) ldr r1, [tsk, #TI_FLAGS] tst r1, #_TIF_WORK_MASK - bne work_pending + bne slow_work_pending no_work_pending: - asm_trace_hardirqs_on + asm_trace_hardirqs_on save = 0 /* perform architecture specific actions before user return */ arch_ret_to_user r1, lr @@ -89,8 +114,8 @@ bl schedule_tail cmp r5, #0 movne r0, r4 - adrne lr, BSYM(1f) - movne pc, r5 + badrne lr, 1f + retne r5 1: get_thread_info tsk b ret_slow_syscall ENDPROC(ret_from_fork) @@ -110,241 +135,6 @@ #undef CALL #define CALL(x) .long x -#ifdef CONFIG_FUNCTION_TRACER -/* - * When compiling with -pg, gcc inserts a call to the mcount routine at the - * start of every function. In mcount, apart from the function's address (in - * lr), we need to get hold of the function's caller's address. - * - * Older GCCs (pre-4.4) inserted a call to a routine called mcount like this: - * - * bl mcount - * - * These versions have the limitation that in order for the mcount routine to - * be able to determine the function's caller's address, an APCS-style frame - * pointer (which is set up with something like the code below) is required. - * - * mov ip, sp - * push {fp, ip, lr, pc} - * sub fp, ip, #4 - * - * With EABI, these frame pointers are not available unless -mapcs-frame is - * specified, and if building as Thumb-2, not even then. - * - * Newer GCCs (4.4+) solve this problem by introducing a new version of mcount, - * with call sites like: - * - * push {lr} - * bl __gnu_mcount_nc - * - * With these compilers, frame pointers are not necessary. - * - * mcount can be thought of as a function called in the middle of a subroutine - * call. As such, it needs to be transparent for both the caller and the - * callee: the original lr needs to be restored when leaving mcount, and no - * registers should be clobbered. (In the __gnu_mcount_nc implementation, we - * clobber the ip register. This is OK because the ARM calling convention - * allows it to be clobbered in subroutines and doesn't use it to hold - * parameters.) - * - * When using dynamic ftrace, we patch out the mcount call by a "mov r0, r0" - * for the mcount case, and a "pop {lr}" for the __gnu_mcount_nc case (see - * arch/arm/kernel/ftrace.c). - */ - -#ifndef CONFIG_OLD_MCOUNT -#if (__GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 4)) -#error Ftrace requires CONFIG_FRAME_POINTER=y with GCC older than 4.4.0. -#endif -#endif - -.macro mcount_adjust_addr rd, rn - bic \rd, \rn, #1 @ clear the Thumb bit if present - sub \rd, \rd, #MCOUNT_INSN_SIZE -.endm - -.macro __mcount suffix - mcount_enter - ldr r0, =ftrace_trace_function - ldr r2, [r0] - adr r0, .Lftrace_stub - cmp r0, r2 - bne 1f - -#ifdef CONFIG_FUNCTION_GRAPH_TRACER - ldr r1, =ftrace_graph_return - ldr r2, [r1] - cmp r0, r2 - bne ftrace_graph_caller\suffix - - ldr r1, =ftrace_graph_entry - ldr r2, [r1] - ldr r0, =ftrace_graph_entry_stub - cmp r0, r2 - bne ftrace_graph_caller\suffix -#endif - - mcount_exit - -1: mcount_get_lr r1 @ lr of instrumented func - mcount_adjust_addr r0, lr @ instrumented function - adr lr, BSYM(2f) - mov pc, r2 -2: mcount_exit -.endm - -.macro __ftrace_caller suffix - mcount_enter - - mcount_get_lr r1 @ lr of instrumented func - mcount_adjust_addr r0, lr @ instrumented function - - .globl ftrace_call\suffix -ftrace_call\suffix: - bl ftrace_stub - -#ifdef CONFIG_FUNCTION_GRAPH_TRACER - .globl ftrace_graph_call\suffix -ftrace_graph_call\suffix: - mov r0, r0 -#endif - - mcount_exit -.endm - -.macro __ftrace_graph_caller - sub r0, fp, #4 @ &lr of instrumented routine (&parent) -#ifdef CONFIG_DYNAMIC_FTRACE - @ called from __ftrace_caller, saved in mcount_enter - ldr r1, [sp, #16] @ instrumented routine (func) - mcount_adjust_addr r1, r1 -#else - @ called from __mcount, untouched in lr - mcount_adjust_addr r1, lr @ instrumented routine (func) -#endif - mov r2, fp @ frame pointer - bl prepare_ftrace_return - mcount_exit -.endm - -#ifdef CONFIG_OLD_MCOUNT -/* - * mcount - */ - -.macro mcount_enter - stmdb sp!, {r0-r3, lr} -.endm - -.macro mcount_get_lr reg - ldr \reg, [fp, #-4] -.endm - -.macro mcount_exit - ldr lr, [fp, #-4] - ldmia sp!, {r0-r3, pc} -.endm - -ENTRY(mcount) -#ifdef CONFIG_DYNAMIC_FTRACE - stmdb sp!, {lr} - ldr lr, [fp, #-4] - ldmia sp!, {pc} -#else - __mcount _old -#endif -ENDPROC(mcount) - -#ifdef CONFIG_DYNAMIC_FTRACE -ENTRY(ftrace_caller_old) - __ftrace_caller _old -ENDPROC(ftrace_caller_old) -#endif - -#ifdef CONFIG_FUNCTION_GRAPH_TRACER -ENTRY(ftrace_graph_caller_old) - __ftrace_graph_caller -ENDPROC(ftrace_graph_caller_old) -#endif - -.purgem mcount_enter -.purgem mcount_get_lr -.purgem mcount_exit -#endif - -/* - * __gnu_mcount_nc - */ - -.macro mcount_enter -/* - * This pad compensates for the push {lr} at the call site. Note that we are - * unable to unwind through a function which does not otherwise save its lr. - */ - UNWIND(.pad #4) - stmdb sp!, {r0-r3, lr} - UNWIND(.save {r0-r3, lr}) -.endm - -.macro mcount_get_lr reg - ldr \reg, [sp, #20] -.endm - -.macro mcount_exit - ldmia sp!, {r0-r3, ip, lr} - mov pc, ip -.endm - -ENTRY(__gnu_mcount_nc) -UNWIND(.fnstart) -#ifdef CONFIG_DYNAMIC_FTRACE - mov ip, lr - ldmia sp!, {lr} - mov pc, ip -#else - __mcount -#endif -UNWIND(.fnend) -ENDPROC(__gnu_mcount_nc) - -#ifdef CONFIG_DYNAMIC_FTRACE -ENTRY(ftrace_caller) -UNWIND(.fnstart) - __ftrace_caller -UNWIND(.fnend) -ENDPROC(ftrace_caller) -#endif - -#ifdef CONFIG_FUNCTION_GRAPH_TRACER -ENTRY(ftrace_graph_caller) -UNWIND(.fnstart) - __ftrace_graph_caller -UNWIND(.fnend) -ENDPROC(ftrace_graph_caller) -#endif - -.purgem mcount_enter -.purgem mcount_get_lr -.purgem mcount_exit - -#ifdef CONFIG_FUNCTION_GRAPH_TRACER - .globl return_to_handler -return_to_handler: - stmdb sp!, {r0-r3} - mov r0, fp @ frame pointer - bl ftrace_return_to_handler - mov lr, r0 @ r0 has real ret addr - ldmia sp!, {r0-r3} - mov pc, lr -#endif - -ENTRY(ftrace_stub) -.Lftrace_stub: - mov pc, lr -ENDPROC(ftrace_stub) - -#endif /* CONFIG_FUNCTION_TRACER */ - /*============================================================================= * SWI handler *----------------------------------------------------------------------------- @@ -352,6 +142,9 @@ .align 5 ENTRY(vector_swi) +#ifdef CONFIG_CPU_V7M + v7m_exception_entry +#else sub sp, sp, #S_FRAME_SIZE stmia sp, {r0 - r12} @ Calling r0 - r12 ARM( add r8, sp, #S_PC ) @@ -362,14 +155,9 @@ str lr, [sp, #S_PC] @ Save calling PC str r8, [sp, #S_PSR] @ Save CPSR str r0, [sp, #S_OLD_R0] @ Save OLD_R0 - zero_fp - -#ifdef CONFIG_ALIGNMENT_TRAP - ldr ip, __cr_alignment - ldr ip, [ip] - mcr p15, 0, ip, c1, c0 @ update control register #endif - + zero_fp + alignment_trap r10, ip, __cr_alignment enable_irq ct_user_exit get_thread_info tsk @@ -391,9 +179,7 @@ #else USER( ldr r10, [lr, #-4] ) @ get SWI instruction #endif -#ifdef CONFIG_CPU_ENDIAN_BE8 - rev r10, r10 @ little endian instruction -#endif + ARM_BE8(rev r10, r10) @ little endian instruction #elif defined(CONFIG_AEABI) @@ -411,6 +197,8 @@ USER( ldr scno, [lr, #-4] ) @ get SWI instruction #endif + uaccess_disable tbl + adr tbl, sys_call_table @ load syscall table pointer #if defined(CONFIG_OABI_COMPAT) @@ -436,14 +224,14 @@ bne __sys_trace cmp scno, #NR_syscalls @ check upper syscall limit - adr lr, BSYM(ret_fast_syscall) @ return address + badr lr, ret_fast_syscall @ return address ldrcc pc, [tbl, scno, lsl #2] @ call sys_* routine add r1, sp, #S_OFF -2: mov why, #0 @ no longer a real syscall - cmp scno, #(__ARM_NR_BASE - __NR_SYSCALL_BASE) +2: cmp scno, #(__ARM_NR_BASE - __NR_SYSCALL_BASE) eor r0, scno, #__NR_SYSCALL_BASE @ put OS number back - bcs arm_syscall + bcs arm_syscall + mov why, #0 @ no longer a real syscall b sys_ni_syscall @ not private func #if defined(CONFIG_OABI_COMPAT) || !defined(CONFIG_AEABI) @@ -471,7 +259,7 @@ add r0, sp, #S_OFF bl syscall_trace_enter - adr lr, BSYM(__sys_trace_return) @ return address + badr lr, __sys_trace_return @ return address mov scno, r0 @ syscall number (possibly new) add r1, sp, #S_R0 + S_OFF @ pointer to regs cmp scno, #NR_syscalls @ check upper syscall limit @@ -489,6 +277,12 @@ bl syscall_trace_exit b ret_slow_syscall +__sys_trace_return_nosave: + enable_irq_notrace + mov r0, sp + bl syscall_trace_exit + b ret_slow_syscall + .align 5 #ifdef CONFIG_ALIGNMENT_TRAP .type __cr_alignment, #object @@ -567,7 +361,7 @@ streq r5, [sp, #4] beq sys_mmap_pgoff mov r0, #-EINVAL - mov pc, lr + ret lr #else str r5, [sp, #4] b sys_mmap_pgoff