diff options
Diffstat (limited to 'usr/src/uts/i86pc/os/startup.c')
| -rw-r--r-- | usr/src/uts/i86pc/os/startup.c | 63 |
1 files changed, 62 insertions, 1 deletions
diff --git a/usr/src/uts/i86pc/os/startup.c b/usr/src/uts/i86pc/os/startup.c index 700b3456ae..a9a7dd57a3 100644 --- a/usr/src/uts/i86pc/os/startup.c +++ b/usr/src/uts/i86pc/os/startup.c @@ -22,7 +22,7 @@ * Copyright (c) 1993, 2010, Oracle and/or its affiliates. All rights reserved. * Copyright 2012 DEY Storage Systems, Inc. All rights reserved. * Copyright 2013 Nexenta Systems, Inc. All rights reserved. - * Copyright 2013 Joyent, Inc. All rights reserved. + * Copyright 2015 Joyent, Inc. */ /* * Copyright (c) 2010, Intel Corporation. @@ -284,6 +284,12 @@ int segzio_fromheap = 1; #endif /* + * Give folks an escape hatch for disabling SMAP via kmdb. Doesn't work + * post-boot. + */ +int disable_smap = 0; + +/* * new memory fragmentations are possible in startup() due to BOP_ALLOCs. this * depends on number of BOP_ALLOC calls made and requested size, memory size * combination and whether boot.bin memory needs to be freed. @@ -673,6 +679,60 @@ perform_allocations(void) } /* + * Set up and enable SMAP now before we start other CPUs, but after the kernel's + * VM has been set up so we can use hot_patch_kernel_text(). + * + * We can only patch 1, 2, or 4 bytes, but not three bytes. So instead, we + * replace the four byte word at the patch point. See uts/intel/ia32/ml/copy.s + * for more information on what's going on here. + */ +static void +startup_smap(void) +{ + int i; + uint32_t inst; + uint8_t *instp; + char sym[128]; + + extern int _smap_enable_patch_count; + extern int _smap_disable_patch_count; + + if (disable_smap != 0) + remove_x86_feature(x86_featureset, X86FSET_SMAP); + + if (is_x86_feature(x86_featureset, X86FSET_SMAP) == B_FALSE) + return; + + for (i = 0; i < _smap_enable_patch_count; i++) { + int sizep; + + VERIFY3U(i, <, _smap_enable_patch_count); + VERIFY(snprintf(sym, sizeof (sym), "_smap_enable_patch_%d", i) < + sizeof (sym)); + instp = (uint8_t *)(void *)kobj_getelfsym(sym, NULL, &sizep); + VERIFY(instp != 0); + inst = (instp[3] << 24) | (SMAP_CLAC_INSTR & 0x00ffffff); + hot_patch_kernel_text((caddr_t)instp, inst, 4); + } + + for (i = 0; i < _smap_disable_patch_count; i++) { + int sizep; + + VERIFY(snprintf(sym, sizeof (sym), "_smap_disable_patch_%d", + i) < sizeof (sym)); + instp = (uint8_t *)(void *)kobj_getelfsym(sym, NULL, &sizep); + VERIFY(instp != 0); + inst = (instp[3] << 24) | (SMAP_STAC_INSTR & 0x00ffffff); + hot_patch_kernel_text((caddr_t)instp, inst, 4); + } + + hot_patch_kernel_text((caddr_t)smap_enable, SMAP_CLAC_INSTR, 4); + hot_patch_kernel_text((caddr_t)smap_disable, SMAP_STAC_INSTR, 4); + setcr4(getcr4() | CR4_SMAP); + smap_enable(); +} + +/* * Our world looks like this at startup time. * * In a 32-bit OS, boot loads the kernel text at 0xfe800000 and kernel data @@ -727,6 +787,7 @@ startup(void) * the irq routing table (used for pci labels). */ startup_pci_bios(); + startup_smap(); #endif #if defined(__xpv) startup_xen_mca(); |