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linux/arch/x86/crypto/sha256_ni_asm.S
Linus Torvalds 94a855111e - Add the call depth tracking mitigation for Retbleed which has 
been long in the making. It is a lighterweight software-only fix for
 Skylake-based cores where enabling IBRS is a big hammer and causes a
 significant performance impact.
 
 What it basically does is, it aligns all kernel functions to 16 bytes
 boundary and adds a 16-byte padding before the function, objtool
 collects all functions' locations and when the mitigation gets applied,
 it patches a call accounting thunk which is used to track the call depth
 of the stack at any time.
 
 When that call depth reaches a magical, microarchitecture-specific value
 for the Return Stack Buffer, the code stuffs that RSB and avoids its
 underflow which could otherwise lead to the Intel variant of Retbleed.
 
 This software-only solution brings a lot of the lost performance back,
 as benchmarks suggest:
 
   https://lore.kernel.org/all/20220915111039.092790446@infradead.org/
 
 That page above also contains a lot more detailed explanation of the
 whole mechanism
 
 - Implement a new control flow integrity scheme called FineIBT which is
 based on the software kCFI implementation and uses hardware IBT support
 where present to annotate and track indirect branches using a hash to
 validate them
 
 - Other misc fixes and cleanups
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Merge tag 'x86_core_for_v6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 core updates from Borislav Petkov:

 - Add the call depth tracking mitigation for Retbleed which has been
   long in the making. It is a lighterweight software-only fix for
   Skylake-based cores where enabling IBRS is a big hammer and causes a
   significant performance impact.

   What it basically does is, it aligns all kernel functions to 16 bytes
   boundary and adds a 16-byte padding before the function, objtool
   collects all functions' locations and when the mitigation gets
   applied, it patches a call accounting thunk which is used to track
   the call depth of the stack at any time.

   When that call depth reaches a magical, microarchitecture-specific
   value for the Return Stack Buffer, the code stuffs that RSB and
   avoids its underflow which could otherwise lead to the Intel variant
   of Retbleed.

   This software-only solution brings a lot of the lost performance
   back, as benchmarks suggest:

       https://lore.kernel.org/all/20220915111039.092790446@infradead.org/

   That page above also contains a lot more detailed explanation of the
   whole mechanism

 - Implement a new control flow integrity scheme called FineIBT which is
   based on the software kCFI implementation and uses hardware IBT
   support where present to annotate and track indirect branches using a
   hash to validate them

 - Other misc fixes and cleanups

* tag 'x86_core_for_v6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (80 commits)
  x86/paravirt: Use common macro for creating simple asm paravirt functions
  x86/paravirt: Remove clobber bitmask from .parainstructions
  x86/debug: Include percpu.h in debugreg.h to get DECLARE_PER_CPU() et al
  x86/cpufeatures: Move X86_FEATURE_CALL_DEPTH from bit 18 to bit 19 of word 11, to leave space for WIP X86_FEATURE_SGX_EDECCSSA bit
  x86/Kconfig: Enable kernel IBT by default
  x86,pm: Force out-of-line memcpy()
  objtool: Fix weak hole vs prefix symbol
  objtool: Optimize elf_dirty_reloc_sym()
  x86/cfi: Add boot time hash randomization
  x86/cfi: Boot time selection of CFI scheme
  x86/ibt: Implement FineIBT
  objtool: Add --cfi to generate the .cfi_sites section
  x86: Add prefix symbols for function padding
  objtool: Add option to generate prefix symbols
  objtool: Avoid O(bloody terrible) behaviour -- an ode to libelf
  objtool: Slice up elf_create_section_symbol()
  kallsyms: Revert "Take callthunks into account"
  x86: Unconfuse CONFIG_ and X86_FEATURE_ namespaces
  x86/retpoline: Fix crash printing warning
  x86/paravirt: Fix a !PARAVIRT build warning
  ...
2022-12-14 15:03:00 -08:00

356 lines
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/*
* Intel SHA Extensions optimized implementation of a SHA-256 update function
*
* This file is provided under a dual BSD/GPLv2 license. When using or
* redistributing this file, you may do so under either license.
*
* GPL LICENSE SUMMARY
*
* Copyright(c) 2015 Intel Corporation.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of version 2 of the GNU General Public License as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* Contact Information:
* Sean Gulley <sean.m.gulley@intel.com>
* Tim Chen <tim.c.chen@linux.intel.com>
*
* BSD LICENSE
*
* Copyright(c) 2015 Intel Corporation.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* * Neither the name of Intel Corporation nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
#include <linux/linkage.h>
#include <linux/cfi_types.h>
#define DIGEST_PTR %rdi /* 1st arg */
#define DATA_PTR %rsi /* 2nd arg */
#define NUM_BLKS %rdx /* 3rd arg */
#define SHA256CONSTANTS %rax
#define MSG %xmm0
#define STATE0 %xmm1
#define STATE1 %xmm2
#define MSGTMP0 %xmm3
#define MSGTMP1 %xmm4
#define MSGTMP2 %xmm5
#define MSGTMP3 %xmm6
#define MSGTMP4 %xmm7
#define SHUF_MASK %xmm8
#define ABEF_SAVE %xmm9
#define CDGH_SAVE %xmm10
/*
* Intel SHA Extensions optimized implementation of a SHA-256 update function
*
* The function takes a pointer to the current hash values, a pointer to the
* input data, and a number of 64 byte blocks to process. Once all blocks have
* been processed, the digest pointer is updated with the resulting hash value.
* The function only processes complete blocks, there is no functionality to
* store partial blocks. All message padding and hash value initialization must
* be done outside the update function.
*
* The indented lines in the loop are instructions related to rounds processing.
* The non-indented lines are instructions related to the message schedule.
*
* void sha256_ni_transform(uint32_t *digest, const void *data,
uint32_t numBlocks);
* digest : pointer to digest
* data: pointer to input data
* numBlocks: Number of blocks to process
*/
.text
SYM_TYPED_FUNC_START(sha256_ni_transform)
shl $6, NUM_BLKS /* convert to bytes */
jz .Ldone_hash
add DATA_PTR, NUM_BLKS /* pointer to end of data */
/*
* load initial hash values
* Need to reorder these appropriately
* DCBA, HGFE -> ABEF, CDGH
*/
movdqu 0*16(DIGEST_PTR), STATE0
movdqu 1*16(DIGEST_PTR), STATE1
pshufd $0xB1, STATE0, STATE0 /* CDAB */
pshufd $0x1B, STATE1, STATE1 /* EFGH */
movdqa STATE0, MSGTMP4
palignr $8, STATE1, STATE0 /* ABEF */
pblendw $0xF0, MSGTMP4, STATE1 /* CDGH */
movdqa PSHUFFLE_BYTE_FLIP_MASK(%rip), SHUF_MASK
lea K256(%rip), SHA256CONSTANTS
.Lloop0:
/* Save hash values for addition after rounds */
movdqa STATE0, ABEF_SAVE
movdqa STATE1, CDGH_SAVE
/* Rounds 0-3 */
movdqu 0*16(DATA_PTR), MSG
pshufb SHUF_MASK, MSG
movdqa MSG, MSGTMP0
paddd 0*16(SHA256CONSTANTS), MSG
sha256rnds2 STATE0, STATE1
pshufd $0x0E, MSG, MSG
sha256rnds2 STATE1, STATE0
/* Rounds 4-7 */
movdqu 1*16(DATA_PTR), MSG
pshufb SHUF_MASK, MSG
movdqa MSG, MSGTMP1
paddd 1*16(SHA256CONSTANTS), MSG
sha256rnds2 STATE0, STATE1
pshufd $0x0E, MSG, MSG
sha256rnds2 STATE1, STATE0
sha256msg1 MSGTMP1, MSGTMP0
/* Rounds 8-11 */
movdqu 2*16(DATA_PTR), MSG
pshufb SHUF_MASK, MSG
movdqa MSG, MSGTMP2
paddd 2*16(SHA256CONSTANTS), MSG
sha256rnds2 STATE0, STATE1
pshufd $0x0E, MSG, MSG
sha256rnds2 STATE1, STATE0
sha256msg1 MSGTMP2, MSGTMP1
/* Rounds 12-15 */
movdqu 3*16(DATA_PTR), MSG
pshufb SHUF_MASK, MSG
movdqa MSG, MSGTMP3
paddd 3*16(SHA256CONSTANTS), MSG
sha256rnds2 STATE0, STATE1
movdqa MSGTMP3, MSGTMP4
palignr $4, MSGTMP2, MSGTMP4
paddd MSGTMP4, MSGTMP0
sha256msg2 MSGTMP3, MSGTMP0
pshufd $0x0E, MSG, MSG
sha256rnds2 STATE1, STATE0
sha256msg1 MSGTMP3, MSGTMP2
/* Rounds 16-19 */
movdqa MSGTMP0, MSG
paddd 4*16(SHA256CONSTANTS), MSG
sha256rnds2 STATE0, STATE1
movdqa MSGTMP0, MSGTMP4
palignr $4, MSGTMP3, MSGTMP4
paddd MSGTMP4, MSGTMP1
sha256msg2 MSGTMP0, MSGTMP1
pshufd $0x0E, MSG, MSG
sha256rnds2 STATE1, STATE0
sha256msg1 MSGTMP0, MSGTMP3
/* Rounds 20-23 */
movdqa MSGTMP1, MSG
paddd 5*16(SHA256CONSTANTS), MSG
sha256rnds2 STATE0, STATE1
movdqa MSGTMP1, MSGTMP4
palignr $4, MSGTMP0, MSGTMP4
paddd MSGTMP4, MSGTMP2
sha256msg2 MSGTMP1, MSGTMP2
pshufd $0x0E, MSG, MSG
sha256rnds2 STATE1, STATE0
sha256msg1 MSGTMP1, MSGTMP0
/* Rounds 24-27 */
movdqa MSGTMP2, MSG
paddd 6*16(SHA256CONSTANTS), MSG
sha256rnds2 STATE0, STATE1
movdqa MSGTMP2, MSGTMP4
palignr $4, MSGTMP1, MSGTMP4
paddd MSGTMP4, MSGTMP3
sha256msg2 MSGTMP2, MSGTMP3
pshufd $0x0E, MSG, MSG
sha256rnds2 STATE1, STATE0
sha256msg1 MSGTMP2, MSGTMP1
/* Rounds 28-31 */
movdqa MSGTMP3, MSG
paddd 7*16(SHA256CONSTANTS), MSG
sha256rnds2 STATE0, STATE1
movdqa MSGTMP3, MSGTMP4
palignr $4, MSGTMP2, MSGTMP4
paddd MSGTMP4, MSGTMP0
sha256msg2 MSGTMP3, MSGTMP0
pshufd $0x0E, MSG, MSG
sha256rnds2 STATE1, STATE0
sha256msg1 MSGTMP3, MSGTMP2
/* Rounds 32-35 */
movdqa MSGTMP0, MSG
paddd 8*16(SHA256CONSTANTS), MSG
sha256rnds2 STATE0, STATE1
movdqa MSGTMP0, MSGTMP4
palignr $4, MSGTMP3, MSGTMP4
paddd MSGTMP4, MSGTMP1
sha256msg2 MSGTMP0, MSGTMP1
pshufd $0x0E, MSG, MSG
sha256rnds2 STATE1, STATE0
sha256msg1 MSGTMP0, MSGTMP3
/* Rounds 36-39 */
movdqa MSGTMP1, MSG
paddd 9*16(SHA256CONSTANTS), MSG
sha256rnds2 STATE0, STATE1
movdqa MSGTMP1, MSGTMP4
palignr $4, MSGTMP0, MSGTMP4
paddd MSGTMP4, MSGTMP2
sha256msg2 MSGTMP1, MSGTMP2
pshufd $0x0E, MSG, MSG
sha256rnds2 STATE1, STATE0
sha256msg1 MSGTMP1, MSGTMP0
/* Rounds 40-43 */
movdqa MSGTMP2, MSG
paddd 10*16(SHA256CONSTANTS), MSG
sha256rnds2 STATE0, STATE1
movdqa MSGTMP2, MSGTMP4
palignr $4, MSGTMP1, MSGTMP4
paddd MSGTMP4, MSGTMP3
sha256msg2 MSGTMP2, MSGTMP3
pshufd $0x0E, MSG, MSG
sha256rnds2 STATE1, STATE0
sha256msg1 MSGTMP2, MSGTMP1
/* Rounds 44-47 */
movdqa MSGTMP3, MSG
paddd 11*16(SHA256CONSTANTS), MSG
sha256rnds2 STATE0, STATE1
movdqa MSGTMP3, MSGTMP4
palignr $4, MSGTMP2, MSGTMP4
paddd MSGTMP4, MSGTMP0
sha256msg2 MSGTMP3, MSGTMP0
pshufd $0x0E, MSG, MSG
sha256rnds2 STATE1, STATE0
sha256msg1 MSGTMP3, MSGTMP2
/* Rounds 48-51 */
movdqa MSGTMP0, MSG
paddd 12*16(SHA256CONSTANTS), MSG
sha256rnds2 STATE0, STATE1
movdqa MSGTMP0, MSGTMP4
palignr $4, MSGTMP3, MSGTMP4
paddd MSGTMP4, MSGTMP1
sha256msg2 MSGTMP0, MSGTMP1
pshufd $0x0E, MSG, MSG
sha256rnds2 STATE1, STATE0
sha256msg1 MSGTMP0, MSGTMP3
/* Rounds 52-55 */
movdqa MSGTMP1, MSG
paddd 13*16(SHA256CONSTANTS), MSG
sha256rnds2 STATE0, STATE1
movdqa MSGTMP1, MSGTMP4
palignr $4, MSGTMP0, MSGTMP4
paddd MSGTMP4, MSGTMP2
sha256msg2 MSGTMP1, MSGTMP2
pshufd $0x0E, MSG, MSG
sha256rnds2 STATE1, STATE0
/* Rounds 56-59 */
movdqa MSGTMP2, MSG
paddd 14*16(SHA256CONSTANTS), MSG
sha256rnds2 STATE0, STATE1
movdqa MSGTMP2, MSGTMP4
palignr $4, MSGTMP1, MSGTMP4
paddd MSGTMP4, MSGTMP3
sha256msg2 MSGTMP2, MSGTMP3
pshufd $0x0E, MSG, MSG
sha256rnds2 STATE1, STATE0
/* Rounds 60-63 */
movdqa MSGTMP3, MSG
paddd 15*16(SHA256CONSTANTS), MSG
sha256rnds2 STATE0, STATE1
pshufd $0x0E, MSG, MSG
sha256rnds2 STATE1, STATE0
/* Add current hash values with previously saved */
paddd ABEF_SAVE, STATE0
paddd CDGH_SAVE, STATE1
/* Increment data pointer and loop if more to process */
add $64, DATA_PTR
cmp NUM_BLKS, DATA_PTR
jne .Lloop0
/* Write hash values back in the correct order */
pshufd $0x1B, STATE0, STATE0 /* FEBA */
pshufd $0xB1, STATE1, STATE1 /* DCHG */
movdqa STATE0, MSGTMP4
pblendw $0xF0, STATE1, STATE0 /* DCBA */
palignr $8, MSGTMP4, STATE1 /* HGFE */
movdqu STATE0, 0*16(DIGEST_PTR)
movdqu STATE1, 1*16(DIGEST_PTR)
.Ldone_hash:
RET
SYM_FUNC_END(sha256_ni_transform)
.section .rodata.cst256.K256, "aM", @progbits, 256
.align 64
K256:
.long 0x428a2f98,0x71374491,0xb5c0fbcf,0xe9b5dba5
.long 0x3956c25b,0x59f111f1,0x923f82a4,0xab1c5ed5
.long 0xd807aa98,0x12835b01,0x243185be,0x550c7dc3
.long 0x72be5d74,0x80deb1fe,0x9bdc06a7,0xc19bf174
.long 0xe49b69c1,0xefbe4786,0x0fc19dc6,0x240ca1cc
.long 0x2de92c6f,0x4a7484aa,0x5cb0a9dc,0x76f988da
.long 0x983e5152,0xa831c66d,0xb00327c8,0xbf597fc7
.long 0xc6e00bf3,0xd5a79147,0x06ca6351,0x14292967
.long 0x27b70a85,0x2e1b2138,0x4d2c6dfc,0x53380d13
.long 0x650a7354,0x766a0abb,0x81c2c92e,0x92722c85
.long 0xa2bfe8a1,0xa81a664b,0xc24b8b70,0xc76c51a3
.long 0xd192e819,0xd6990624,0xf40e3585,0x106aa070
.long 0x19a4c116,0x1e376c08,0x2748774c,0x34b0bcb5
.long 0x391c0cb3,0x4ed8aa4a,0x5b9cca4f,0x682e6ff3
.long 0x748f82ee,0x78a5636f,0x84c87814,0x8cc70208
.long 0x90befffa,0xa4506ceb,0xbef9a3f7,0xc67178f2
.section .rodata.cst16.PSHUFFLE_BYTE_FLIP_MASK, "aM", @progbits, 16
.align 16
PSHUFFLE_BYTE_FLIP_MASK:
.octa 0x0c0d0e0f08090a0b0405060700010203
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