diff options
Diffstat (limited to 'arch/s390/kernel/nospec-branch.c')
| -rw-r--r-- | arch/s390/kernel/nospec-branch.c | 31 |
1 files changed, 5 insertions, 26 deletions
diff --git a/arch/s390/kernel/nospec-branch.c b/arch/s390/kernel/nospec-branch.c index 60e6fec27bba..717bbcc056e5 100644 --- a/arch/s390/kernel/nospec-branch.c +++ b/arch/s390/kernel/nospec-branch.c @@ -105,6 +105,7 @@ static void __init_or_module __nospec_revert(s32 *start, s32 *end) s32 *epo; /* Second part of the instruction replace is always a nop */ + memcpy(insnbuf + 2, branch, sizeof(branch)); for (epo = start; epo < end; epo++) { instr = (u8 *) epo + *epo; if (instr[0] == 0xc0 && (instr[1] & 0x0f) == 0x04) @@ -117,42 +118,20 @@ static void __init_or_module __nospec_revert(s32 *start, s32 *end) if (thunk[0] == 0xc6 && thunk[1] == 0x00) /* exrl %r0,<target-br> */ br = thunk + (*(int *)(thunk + 2)) * 2; - else if (thunk[0] == 0xc0 && (thunk[1] & 0x0f) == 0x00 && - thunk[6] == 0x44 && thunk[7] == 0x00 && - (thunk[8] & 0x0f) == 0x00 && thunk[9] == 0x00 && - (thunk[1] & 0xf0) == (thunk[8] & 0xf0)) - /* larl %rx,<target br> + ex %r0,0(%rx) */ - br = thunk + (*(int *)(thunk + 2)) * 2; else continue; - /* Check for unconditional branch 0x07f? or 0x47f???? */ - if ((br[0] & 0xbf) != 0x07 || (br[1] & 0xf0) != 0xf0) + if (br[0] != 0x07 || (br[1] & 0xf0) != 0xf0) continue; - - memcpy(insnbuf + 2, branch, sizeof(branch)); switch (type) { case BRCL_EXPOLINE: + /* brcl to thunk, replace with br + nop */ insnbuf[0] = br[0]; insnbuf[1] = (instr[1] & 0xf0) | (br[1] & 0x0f); - if (br[0] == 0x47) { - /* brcl to b, replace with bc + nopr */ - insnbuf[2] = br[2]; - insnbuf[3] = br[3]; - } else { - /* brcl to br, replace with bcr + nop */ - } break; case BRASL_EXPOLINE: + /* brasl to thunk, replace with basr + nop */ + insnbuf[0] = 0x0d; insnbuf[1] = (instr[1] & 0xf0) | (br[1] & 0x0f); - if (br[0] == 0x47) { - /* brasl to b, replace with bas + nopr */ - insnbuf[0] = 0x4d; - insnbuf[2] = br[2]; - insnbuf[3] = br[3]; - } else { - /* brasl to br, replace with basr + nop */ - insnbuf[0] = 0x0d; - } break; } |