arch/tile: enable single-step support for TILE-Gx (233325b9) · Commits · 戴 / test

arch/tile/include/asm/traps.h

+4 −0

Original line number	Diff line number	Diff line
		@@ -59,4 +59,8 @@ void do_hardwall_trap(struct pt_regs *, int fault_num);
		void do_breakpoint(struct pt_regs *, int fault_num);


		#ifdef __tilegx__
		void gx_singlestep_handle(struct pt_regs *, int fault_num);
		#endif

		#endif /* _ASM_TILE_SYSCALLS_H */

arch/tile/kernel/intvec_32.S

+6 −1

Original line number	Diff line number	Diff line
		@@ -1472,7 +1472,12 @@ handle_ill:
		lw r26, r24
		sw r28, r26

		/* Clear TIF_SINGLESTEP */
		/*
		* Clear TIF_SINGLESTEP to prevent recursion if we execute an ill.
		* The normal non-arch flow redundantly clears TIF_SINGLESTEP, but we
		* need to clear it here and can't really impose on all other arches.
		* So what's another write between friends?
		*/
		GET_THREAD_INFO(r0)

		addi r1, r0, THREAD_INFO_FLAGS_OFFSET

arch/tile/kernel/single_step.c

+72 −1

Original line number	Diff line number	Diff line
		@@ -15,7 +15,7 @@
		* Derived from iLib's single-stepping code.
		*/

		#ifndef __tilegx__ /* No support for single-step yet. */
		#ifndef __tilegx__ /* Hardware support for single step unavailable. */

		/* These functions are only used on the TILE platform */
		#include <linux/slab.h>
		@@ -660,4 +660,75 @@ void single_step_once(struct pt_regs *regs)
		regs->pc += 8;
		}

		#else
		#include <linux/smp.h>
		#include <linux/ptrace.h>
		#include <arch/spr_def.h>

		static DEFINE_PER_CPU(unsigned long, ss_saved_pc);


		/*
		* Called directly on the occasion of an interrupt.
		*
		* If the process doesn't have single step set, then we use this as an
		* opportunity to turn single step off.
		*
		* It has been mentioned that we could conditionally turn off single stepping
		* on each entry into the kernel and rely on single_step_once to turn it
		* on for the processes that matter (as we already do), but this
		* implementation is somewhat more efficient in that we muck with registers
		* once on a bum interrupt rather than on every entry into the kernel.
		*
		* If SINGLE_STEP_CONTROL_K has CANCELED set, then an interrupt occurred,
		* so we have to run through this process again before we can say that an
		* instruction has executed.
		*
		* swint will set CANCELED, but it's a legitimate instruction. Fortunately
		* it changes the PC. If it hasn't changed, then we know that the interrupt
		* wasn't generated by swint and we'll need to run this process again before
		* we can say an instruction has executed.
		*
		* If either CANCELED == 0 or the PC's changed, we send out SIGTRAPs and get
		* on with our lives.
		*/

		void gx_singlestep_handle(struct pt_regs *regs, int fault_num)
		{
		unsigned long *ss_pc = &__get_cpu_var(ss_saved_pc);
		struct thread_info info = (void )current_thread_info();
		int is_single_step = test_ti_thread_flag(info, TIF_SINGLESTEP);
		unsigned long control = __insn_mfspr(SPR_SINGLE_STEP_CONTROL_K);

		if (is_single_step == 0) {
		__insn_mtspr(SPR_SINGLE_STEP_EN_K_K, 0);

		} else if ((*ss_pc != regs->pc) \|\|
		(!(control & SPR_SINGLE_STEP_CONTROL_1__CANCELED_MASK))) {

		ptrace_notify(SIGTRAP);
		control \|= SPR_SINGLE_STEP_CONTROL_1__CANCELED_MASK;
		control \|= SPR_SINGLE_STEP_CONTROL_1__INHIBIT_MASK;
		__insn_mtspr(SPR_SINGLE_STEP_CONTROL_K, control);
		}
		}


		/*
		* Called from need_singlestep. Set up the control registers and the enable
		* register, then return back.
		*/

		void single_step_once(struct pt_regs *regs)
		{
		unsigned long *ss_pc = &__get_cpu_var(ss_saved_pc);
		unsigned long control = __insn_mfspr(SPR_SINGLE_STEP_CONTROL_K);

		*ss_pc = regs->pc;
		control \|= SPR_SINGLE_STEP_CONTROL_1__CANCELED_MASK;
		control \|= SPR_SINGLE_STEP_CONTROL_1__INHIBIT_MASK;
		__insn_mtspr(SPR_SINGLE_STEP_CONTROL_K, control);
		__insn_mtspr(SPR_SINGLE_STEP_EN_K_K, 1 << USER_PL);
		}

		#endif /* !__tilegx__ */

arch/tile/kernel/traps.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -260,7 +260,7 @@ void __kprobes do_trap(struct pt_regs *regs, int fault_num,
		address = regs->pc;
		break;
		case INT_UNALIGN_DATA:
		#ifndef __tilegx__ /* FIXME: GX: no single-step yet */
		#ifndef __tilegx__ /* Emulated support for single step debugging */
		if (unaligned_fixup >= 0) {
		struct single_step_state *state =
		current_thread_info()->step_state;

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