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: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/bad58c66859b2a475c0ad516b53164ae3b4853cd.1618927318.git.christophe.leroy@csgroup.eu

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 475d77a..d2e31a5 100644 (file)
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -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

diff --git a/arch/powerpc/kernel/optprobes.c b/arch/powerpc/kernel/optprobes.c
index 58fdb9f..cdf8708 100644 (file)
--- a/arch/powerpc/kernel/optprobes.c
+++ b/arch/powerpc/kernel/optprobes.c
@@ -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

diff --git a/arch/powerpc/kernel/optprobes_head.S b/arch/powerpc/kernel/optprobes_head.S
index ff8ba4d..19ea331 100644 (file)
--- a/arch/powerpc/kernel/optprobes_head.S
+++ b/arch/powerpc/kernel/optprobes_head.S
@@ -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