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powerpc/kprobes: Roll IS_RFI() macro into IS_RFID() 

In kprobes and xmon, we should exclude both 32-bit and 64-bit variants
of mtmsr and rfi instructions from being stepped. Have IS_RFID() also
detect a rfi instruction similar to IS_MTMSRD().

Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/eee32e1b75dae85d471c89b4c0a123ad4b0aabf8.1621416666.git.naveen.n.rao@linux.vnet.ibm.com
This commit is contained in:
Naveen N. Rao 2021-05-19 16:17:18 +05:30 committed by Michael Ellerman
parent de21e1377c
commit 0566fa760d
2 changed files with 5 additions and 6 deletions
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7
arch/powerpc/include/asm/sstep.h
View File

@ -13,12 +13,11 @@ struct pt_regs;
* we don't allow putting a breakpoint on an mtmsrd instruction.
* Similarly we don't allow breakpoints on rfid instructions.
* These macros tell us if an instruction is a mtmsrd or rfid.
* Note that IS_MTMSRD returns true for both an mtmsr (32-bit)
* and an mtmsrd (64-bit).
* Note that these return true for both mtmsr/rfi (32-bit)
* and mtmsrd/rfid (64-bit).
*/
#define IS_MTMSRD(instr) ((ppc_inst_val(instr) & 0xfc0007be) == 0x7c000124)
#define IS_RFID(instr) ((ppc_inst_val(instr) & 0xfc0007fe) == 0x4c000024)
#define IS_RFI(instr) ((ppc_inst_val(instr) & 0xfc0007fe) == 0x4c000064)
#define IS_RFID(instr) ((ppc_inst_val(instr) & 0xfc0007be) == 0x4c000024)
enum instruction_type {
COMPUTE, /* arith/logical/CR op, etc. */

4
arch/powerpc/kernel/kprobes.c
View File

@ -129,8 +129,8 @@ int arch_prepare_kprobe(struct kprobe *p)
if ((unsigned long)p->addr & 0x03) {
printk("Attempt to register kprobe at an unaligned address\n");
ret = -EINVAL;
} else if (IS_MTMSRD(insn) || IS_RFID(insn) || IS_RFI(insn)) {
printk("Cannot register a kprobe on rfi/rfid or mtmsr[d]\n");
} else if (IS_MTMSRD(insn) || IS_RFID(insn)) {
printk("Cannot register a kprobe on mtmsr[d]/rfi[d]\n");
ret = -EINVAL;
} else if ((unsigned long)p->addr & ~PAGE_MASK &&
ppc_inst_prefixed(ppc_inst_read(p->addr - 1))) {