diff options
Diffstat (limited to 'arch/mips/include')
| -rw-r--r-- | arch/mips/include/asm/asm-prototypes.h | 1 | ||||
| -rw-r--r-- | arch/mips/include/asm/atomic.h | 4 | ||||
| -rw-r--r-- | arch/mips/include/asm/compiler.h | 35 | ||||
| -rw-r--r-- | arch/mips/include/asm/mmu_context.h | 1 | ||||
| -rw-r--r-- | arch/mips/include/asm/tlbex.h | 9 |
5 files changed, 49 insertions, 1 deletions
diff --git a/arch/mips/include/asm/asm-prototypes.h b/arch/mips/include/asm/asm-prototypes.h index 576f1a62dea9..f901ed043c71 100644 --- a/arch/mips/include/asm/asm-prototypes.h +++ b/arch/mips/include/asm/asm-prototypes.h @@ -5,3 +5,4 @@ #include <asm-generic/asm-prototypes.h> #include <linux/uaccess.h> #include <asm/ftrace.h> +#include <asm/mmu_context.h> diff --git a/arch/mips/include/asm/atomic.h b/arch/mips/include/asm/atomic.h index 0269b3de8b51..d4ea7a5b60cf 100644 --- a/arch/mips/include/asm/atomic.h +++ b/arch/mips/include/asm/atomic.h @@ -122,8 +122,8 @@ static __inline__ int atomic_fetch_##op##_relaxed(int i, atomic_t * v) \ " " #asm_op " %0, %1, %3 \n" \ " sc %0, %2 \n" \ "\t" __scbeqz " %0, 1b \n" \ - " move %0, %1 \n" \ " .set mips0 \n" \ + " move %0, %1 \n" \ : "=&r" (result), "=&r" (temp), \ "+" GCC_OFF_SMALL_ASM() (v->counter) \ : "Ir" (i)); \ @@ -190,9 +190,11 @@ static __inline__ int atomic_sub_if_positive(int i, atomic_t * v) __asm__ __volatile__( " .set "MIPS_ISA_LEVEL" \n" "1: ll %1, %2 # atomic_sub_if_positive\n" + " .set mips0 \n" " subu %0, %1, %3 \n" " move %1, %0 \n" " bltz %0, 1f \n" + " .set "MIPS_ISA_LEVEL" \n" " sc %1, %2 \n" "\t" __scbeqz " %1, 1b \n" "1: \n" diff --git a/arch/mips/include/asm/compiler.h b/arch/mips/include/asm/compiler.h index e081a265f422..cc2eb1b06050 100644 --- a/arch/mips/include/asm/compiler.h +++ b/arch/mips/include/asm/compiler.h @@ -8,6 +8,41 @@ #ifndef _ASM_COMPILER_H #define _ASM_COMPILER_H +/* + * With GCC 4.5 onwards we can use __builtin_unreachable to indicate to the + * compiler that a particular code path will never be hit. This allows it to be + * optimised out of the generated binary. + * + * Unfortunately at least GCC 4.6.3 through 7.3.0 inclusive suffer from a bug + * that can lead to instructions from beyond an unreachable statement being + * incorrectly reordered into earlier delay slots if the unreachable statement + * is the only content of a case in a switch statement. This can lead to + * seemingly random behaviour, such as invalid memory accesses from incorrectly + * reordered loads or stores. See this potential GCC fix for details: + * + * https://gcc.gnu.org/ml/gcc-patches/2015-09/msg00360.html + * + * It is unclear whether GCC 8 onwards suffer from the same issue - nothing + * relevant is mentioned in GCC 8 release notes and nothing obviously relevant + * stands out in GCC commit logs, but these newer GCC versions generate very + * different code for the testcase which doesn't exhibit the bug. + * + * GCC also handles stack allocation suboptimally when calling noreturn + * functions or calling __builtin_unreachable(): + * + * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82365 + * + * We work around both of these issues by placing a volatile asm statement, + * which GCC is prevented from reordering past, prior to __builtin_unreachable + * calls. + * + * The .insn statement is required to ensure that any branches to the + * statement, which sadly must be kept due to the asm statement, are known to + * be branches to code and satisfy linker requirements for microMIPS kernels. + */ +#undef barrier_before_unreachable +#define barrier_before_unreachable() asm volatile(".insn") + #if __GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 4) #define GCC_IMM_ASM() "n" #define GCC_REG_ACCUM "$0" diff --git a/arch/mips/include/asm/mmu_context.h b/arch/mips/include/asm/mmu_context.h index b509371a6b0c..94414561de0e 100644 --- a/arch/mips/include/asm/mmu_context.h +++ b/arch/mips/include/asm/mmu_context.h @@ -32,6 +32,7 @@ do { \ } while (0) extern void tlbmiss_handler_setup_pgd(unsigned long); +extern char tlbmiss_handler_setup_pgd_end[]; /* Note: This is also implemented with uasm in arch/mips/kvm/entry.c */ #define TLBMISS_HANDLER_SETUP_PGD(pgd) \ diff --git a/arch/mips/include/asm/tlbex.h b/arch/mips/include/asm/tlbex.h index 4ed7ebed3bf1..6d97e23f30ab 100644 --- a/arch/mips/include/asm/tlbex.h +++ b/arch/mips/include/asm/tlbex.h @@ -24,4 +24,13 @@ void build_tlb_write_entry(u32 **p, struct uasm_label **l, struct uasm_reloc **r, enum tlb_write_entry wmode); +extern void handle_tlbl(void); +extern char handle_tlbl_end[]; + +extern void handle_tlbs(void); +extern char handle_tlbs_end[]; + +extern void handle_tlbm(void); +extern char handle_tlbm_end[]; + #endif /* __ASM_TLBEX_H */ |