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author | 2019-01-04 22:07:47 +1100 | |
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committer | 2019-01-04 22:07:47 +1100 | |
commit | d538d94f0ca86cfedc892cc427169219acb3c2f7 (patch) | |
tree | 8363c4ff35907edb5245da737d7f6982bf22b945 /arch/xtensa/include/asm/jump_label.h | |
parent | KVM: PPC: Book3S HV: radix: Fix uninitialized var build error (diff) | |
parent | Remove 'type' argument from access_ok() function (diff) | |
download | linux-dev-d538d94f0ca86cfedc892cc427169219acb3c2f7.tar.xz linux-dev-d538d94f0ca86cfedc892cc427169219acb3c2f7.zip |
Merge branch 'master' into fixes
We have a fix to apply on top of commit 96d4f267e40f ("Remove 'type'
argument from access_ok() function"), so merge master to get it.
Diffstat (limited to 'arch/xtensa/include/asm/jump_label.h')
-rw-r--r-- | arch/xtensa/include/asm/jump_label.h | 65 |
1 files changed, 65 insertions, 0 deletions
diff --git a/arch/xtensa/include/asm/jump_label.h b/arch/xtensa/include/asm/jump_label.h new file mode 100644 index 000000000000..c812bf85021c --- /dev/null +++ b/arch/xtensa/include/asm/jump_label.h @@ -0,0 +1,65 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* Copyright (C) 2018 Cadence Design Systems Inc. */ + +#ifndef _ASM_XTENSA_JUMP_LABEL_H +#define _ASM_XTENSA_JUMP_LABEL_H + +#ifndef __ASSEMBLY__ + +#include <linux/types.h> + +#define JUMP_LABEL_NOP_SIZE 3 + +static __always_inline bool arch_static_branch(struct static_key *key, + bool branch) +{ + asm_volatile_goto("1:\n\t" + "_nop\n\t" + ".pushsection __jump_table, \"aw\"\n\t" + ".word 1b, %l[l_yes], %c0\n\t" + ".popsection\n\t" + : : "i" (&((char *)key)[branch]) : : l_yes); + + return false; +l_yes: + return true; +} + +static __always_inline bool arch_static_branch_jump(struct static_key *key, + bool branch) +{ + /* + * Xtensa assembler will mark certain points in the code + * as unreachable, so that later assembler or linker relaxation + * passes could use them. A spot right after the J instruction + * is one such point. Assembler and/or linker may insert padding + * or literals here, breaking code flow in case the J instruction + * is later replaced with NOP. Put a label right after the J to + * make it reachable and wrap both into a no-transform block + * to avoid any assembler interference with this. + */ + asm_volatile_goto("1:\n\t" + ".begin no-transform\n\t" + "_j %l[l_yes]\n\t" + "2:\n\t" + ".end no-transform\n\t" + ".pushsection __jump_table, \"aw\"\n\t" + ".word 1b, %l[l_yes], %c0\n\t" + ".popsection\n\t" + : : "i" (&((char *)key)[branch]) : : l_yes); + + return false; +l_yes: + return true; +} + +typedef u32 jump_label_t; + +struct jump_entry { + jump_label_t code; + jump_label_t target; + jump_label_t key; +}; + +#endif /* __ASSEMBLY__ */ +#endif |