Commit eacf4c02 authored by Christophe Leroy's avatar Christophe Leroy Committed by Michael Ellerman
Browse files

powerpc: Enable OPTPROBES on PPC32 



For that, create a 32 bits version of patch_imm64_load_insns()
and create a patch_imm_load_insns() which calls
patch_imm32_load_insns() on PPC32 and patch_imm64_load_insns()
on PPC64.

Adapt optprobes_head.S for PPC32. Use PPC_LL/PPC_STL macros instead
of raw ld/std, opt out things linked to paca and use stmw/lmw to
save/restore registers.

Signed-off-by: default avatarChristophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/bad58c66859b2a475c0ad516b53164ae3b4853cd.1618927318.git.christophe.leroy@csgroup.eu
parent 693557eb

arch/powerpc/Kconfig

+1 −1
Original line number Diff line number Diff line
@@ -229,7 +229,7 @@ config PPC 
	select HAVE_MOD_ARCH_SPECIFIC

	select HAVE_NMI				if PERF_EVENTS || (PPC64 && PPC_BOOK3S)

	select HAVE_HARDLOCKUP_DETECTOR_ARCH	if PPC64 && PPC_BOOK3S && SMP

	select HAVE_OPTPROBES			if PPC64

	select HAVE_OPTPROBES

	select HAVE_PERF_EVENTS

	select HAVE_PERF_EVENTS_NMI		if PPC64

	select HAVE_HARDLOCKUP_DETECTOR_PERF	if PERF_EVENTS && HAVE_PERF_EVENTS_NMI && !HAVE_HARDLOCKUP_DETECTOR_ARCH

arch/powerpc/kernel/optprobes.c

+21 −3
Original line number Diff line number Diff line
@@ -141,11 +141,21 @@ void arch_remove_optimized_kprobe(struct optimized_kprobe *op) 
	}

}



static void patch_imm32_load_insns(unsigned long val, int reg, kprobe_opcode_t *addr)

{

	patch_instruction((struct ppc_inst *)addr,

			  ppc_inst(PPC_RAW_LIS(reg, IMM_H(val))));

	addr++;



	patch_instruction((struct ppc_inst *)addr,

			  ppc_inst(PPC_RAW_ORI(reg, reg, IMM_L(val))));

}



/*

 * Generate instructions to load provided immediate 64-bit value

 * to register 'reg' and patch these instructions at 'addr'.

 */

static void patch_imm64_load_insns(unsigned long val, int reg, kprobe_opcode_t *addr)

static void patch_imm64_load_insns(unsigned long long val, int reg, kprobe_opcode_t *addr)

{

	/* lis reg,(op)@highest */

	patch_instruction((struct ppc_inst *)addr,
@@ -177,6 +187,14 @@ static void patch_imm64_load_insns(unsigned long val, int reg, kprobe_opcode_t * 
				   ___PPC_RS(reg) | (val & 0xffff)));

}



static void patch_imm_load_insns(unsigned long val, int reg, kprobe_opcode_t *addr)

{

	if (IS_ENABLED(CONFIG_PPC64))

		patch_imm64_load_insns(val, reg, addr);

	else

		patch_imm32_load_insns(val, reg, addr);

}



int arch_prepare_optimized_kprobe(struct optimized_kprobe *op, struct kprobe *p)

{

	struct ppc_inst branch_op_callback, branch_emulate_step, temp;
@@ -230,7 +248,7 @@ int arch_prepare_optimized_kprobe(struct optimized_kprobe *op, struct kprobe *p) 
	 * Fixup the template with instructions to:

	 * 1. load the address of the actual probepoint

	 */

	patch_imm64_load_insns((unsigned long)op, 3, buff + TMPL_OP_IDX);

	patch_imm_load_insns((unsigned long)op, 3, buff + TMPL_OP_IDX);



	/*

	 * 2. branch to optimized_callback() and emulate_step()
@@ -264,7 +282,7 @@ int arch_prepare_optimized_kprobe(struct optimized_kprobe *op, struct kprobe *p) 
	 * 3. load instruction to be emulated into relevant register, and

	 */

	temp = ppc_inst_read((struct ppc_inst *)p->ainsn.insn);

	patch_imm64_load_insns(ppc_inst_as_ulong(temp), 4, buff + TMPL_INSN_IDX);

	patch_imm_load_insns(ppc_inst_as_ulong(temp), 4, buff + TMPL_INSN_IDX);



	/*

	 * 4. branch back from trampoline

arch/powerpc/kernel/optprobes_head.S

+34 −31
Original line number Diff line number Diff line
@@ -9,6 +9,16 @@ 
#include <asm/ptrace.h>

#include <asm/asm-offsets.h>



#ifdef CONFIG_PPC64

#define SAVE_30GPRS(base) SAVE_10GPRS(2,base); SAVE_10GPRS(12,base); SAVE_10GPRS(22,base)

#define REST_30GPRS(base) REST_10GPRS(2,base); REST_10GPRS(12,base); REST_10GPRS(22,base)

#define TEMPLATE_FOR_IMM_LOAD_INSNS	nop; nop; nop; nop; nop

#else

#define SAVE_30GPRS(base) stmw	r2, GPR2(base)

#define REST_30GPRS(base) lmw	r2, GPR2(base)

#define TEMPLATE_FOR_IMM_LOAD_INSNS	nop; nop; nop

#endif



#define	OPT_SLOT_SIZE	65536



	.balign	4
@@ -30,39 +40,41 @@ optinsn_slot: 
	.global optprobe_template_entry

optprobe_template_entry:

	/* Create an in-memory pt_regs */

	stdu	r1,-INT_FRAME_SIZE(r1)

	PPC_STLU	r1,-INT_FRAME_SIZE(r1)

	SAVE_GPR(0,r1)

	/* Save the previous SP into stack */

	addi	r0,r1,INT_FRAME_SIZE

	std	r0,GPR1(r1)

	SAVE_10GPRS(2,r1)

	SAVE_10GPRS(12,r1)

	SAVE_10GPRS(22,r1)

	PPC_STL	r0,GPR1(r1)

	SAVE_30GPRS(r1)

	/* Save SPRS */

	mfmsr	r5

	std	r5,_MSR(r1)

	PPC_STL	r5,_MSR(r1)

	li	r5,0x700

	std	r5,_TRAP(r1)

	PPC_STL	r5,_TRAP(r1)

	li	r5,0

	std	r5,ORIG_GPR3(r1)

	std	r5,RESULT(r1)

	PPC_STL	r5,ORIG_GPR3(r1)

	PPC_STL	r5,RESULT(r1)

	mfctr	r5

	std	r5,_CTR(r1)

	PPC_STL	r5,_CTR(r1)

	mflr	r5

	std	r5,_LINK(r1)

	PPC_STL	r5,_LINK(r1)

	mfspr	r5,SPRN_XER

	std	r5,_XER(r1)

	PPC_STL	r5,_XER(r1)

	mfcr	r5

	std	r5,_CCR(r1)

	PPC_STL	r5,_CCR(r1)

#ifdef CONFIG_PPC64

	lbz     r5,PACAIRQSOFTMASK(r13)

	std     r5,SOFTE(r1)

#endif



	/*

	 * We may get here from a module, so load the kernel TOC in r2.

	 * The original TOC gets restored when pt_regs is restored

	 * further below.

	 */

#ifdef CONFIG_PPC64

	ld	r2,PACATOC(r13)

#endif



	.global optprobe_template_op_address

optprobe_template_op_address:
@@ -70,11 +82,8 @@ optprobe_template_op_address: 
	 * Parameters to optimized_callback():

	 * 1. optimized_kprobe structure in r3

	 */

	nop

	nop

	nop

	nop

	nop

	TEMPLATE_FOR_IMM_LOAD_INSNS



	/* 2. pt_regs pointer in r4 */

	addi	r4,r1,STACK_FRAME_OVERHEAD
@@ -92,11 +101,7 @@ optprobe_template_call_handler: 
	.global optprobe_template_insn

optprobe_template_insn:

	/* 2, Pass instruction to be emulated in r4 */

	nop

	nop

	nop

	nop

	nop

	TEMPLATE_FOR_IMM_LOAD_INSNS



	.global optprobe_template_call_emulate

optprobe_template_call_emulate:
@@ -107,20 +112,18 @@ optprobe_template_call_emulate: 
	 * All done.

	 * Now, restore the registers...

	 */

	ld	r5,_MSR(r1)

	PPC_LL	r5,_MSR(r1)

	mtmsr	r5

	ld	r5,_CTR(r1)

	PPC_LL	r5,_CTR(r1)

	mtctr	r5

	ld	r5,_LINK(r1)

	PPC_LL	r5,_LINK(r1)

	mtlr	r5

	ld	r5,_XER(r1)

	PPC_LL	r5,_XER(r1)

	mtxer	r5

	ld	r5,_CCR(r1)

	PPC_LL	r5,_CCR(r1)

	mtcr	r5

	REST_GPR(0,r1)

	REST_10GPRS(2,r1)

	REST_10GPRS(12,r1)

	REST_10GPRS(22,r1)

	REST_30GPRS(r1)

	/* Restore the previous SP */

	addi	r1,r1,INT_FRAME_SIZE