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powerpc: Add support for relative exception tables
This halves the exception table size on 64-bit builds, and it allows build-time sorting of exception tables to work on relocated kernels. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> [mpe: Minor asm fixups and bits to keep the selftests working] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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@ -785,9 +785,9 @@ END_FTR_SECTION_IFCLR(CPU_FTR_601)
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*/
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#define EX_TABLE(_fault, _target) \
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stringify_in_c(.section __ex_table,"a";)\
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PPC_LONG_ALIGN stringify_in_c(;) \
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PPC_LONG stringify_in_c(_fault;) \
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PPC_LONG stringify_in_c(_target;) \
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stringify_in_c(.balign 4;) \
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stringify_in_c(.long (_fault) - . ;) \
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stringify_in_c(.long (_target) - . ;) \
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stringify_in_c(.previous)
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#endif /* _ASM_POWERPC_PPC_ASM_H */
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@ -64,23 +64,30 @@
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__access_ok((__force unsigned long)(addr), (size), get_fs()))
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/*
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* The exception table consists of pairs of addresses: the first is the
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* address of an instruction that is allowed to fault, and the second is
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* The exception table consists of pairs of relative addresses: the first is
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* the address of an instruction that is allowed to fault, and the second is
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* the address at which the program should continue. No registers are
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* modified, so it is entirely up to the continuation code to figure out
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* what to do.
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* modified, so it is entirely up to the continuation code to figure out what
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* to do.
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*
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* All the routines below use bits of fixup code that are out of line
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* with the main instruction path. This means when everything is well,
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* we don't even have to jump over them. Further, they do not intrude
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* on our cache or tlb entries.
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* All the routines below use bits of fixup code that are out of line with the
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* main instruction path. This means when everything is well, we don't even
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* have to jump over them. Further, they do not intrude on our cache or tlb
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* entries.
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*/
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#define ARCH_HAS_RELATIVE_EXTABLE
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struct exception_table_entry {
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unsigned long insn;
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unsigned long fixup;
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int insn;
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int fixup;
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};
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static inline unsigned long extable_fixup(const struct exception_table_entry *x)
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{
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return (unsigned long)&x->fixup + x->fixup;
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}
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/*
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* These are the main single-value transfer routines. They automatically
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* use the right size if we just have the right pointer type.
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@ -449,7 +449,7 @@ int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
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* zero, try to fix up.
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*/
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if ((entry = search_exception_tables(regs->nip)) != NULL) {
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regs->nip = entry->fixup;
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regs->nip = extable_fixup(entry);
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return 1;
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}
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@ -365,7 +365,7 @@ static inline int check_io_access(struct pt_regs *regs)
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(*nip & 0x100)? "OUT to": "IN from",
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regs->gpr[rb] - _IO_BASE, nip);
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regs->msr |= MSR_RI;
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regs->nip = entry->fixup;
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regs->nip = extable_fixup(entry);
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return 1;
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}
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}
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@ -512,7 +512,7 @@ void bad_page_fault(struct pt_regs *regs, unsigned long address, int sig)
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/* Are we prepared to handle this fault? */
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if ((entry = search_exception_tables(regs->nip)) != NULL) {
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regs->nip = entry->fixup;
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regs->nip = extable_fixup(entry);
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return;
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}
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@ -263,7 +263,7 @@ static int ppc750_machine_check_exception(struct pt_regs *regs)
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if ((entry = search_exception_tables(regs->nip)) != NULL) {
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tsi108_clear_pci_cfg_error();
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regs->msr |= MSR_RI;
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regs->nip = entry->fixup;
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regs->nip = extable_fixup(entry);
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return 1;
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}
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return 0;
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@ -174,7 +174,7 @@ static int mpc7448_machine_check_exception(struct pt_regs *regs)
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if ((entry = search_exception_tables(regs->nip)) != NULL) {
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tsi108_clear_pci_cfg_error();
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regs->msr |= MSR_RI;
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regs->nip = entry->fixup;
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regs->nip = extable_fixup(entry);
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return 1;
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}
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return 0;
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@ -111,7 +111,7 @@ int fsl_rio_mcheck_exception(struct pt_regs *regs)
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out_be32((u32 *)(rio_regs_win + RIO_LTLEDCSR),
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0);
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regs->msr |= MSR_RI;
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regs->nip = entry->fixup;
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regs->nip = extable_fixup(entry);
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return 1;
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}
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}
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@ -73,19 +73,23 @@ extern char __stop___ex_table[];
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#error implement UCONTEXT_NIA
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#endif
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struct extbl_entry {
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int insn;
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int fixup;
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};
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static void segv_handler(int signr, siginfo_t *info, void *ptr)
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{
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ucontext_t *uc = (ucontext_t *)ptr;
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unsigned long addr = (unsigned long)info->si_addr;
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unsigned long *ip = &UCONTEXT_NIA(uc);
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unsigned long *ex_p = (unsigned long *)__start___ex_table;
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struct extbl_entry *entry = (struct extbl_entry *)__start___ex_table;
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while (ex_p < (unsigned long *)__stop___ex_table) {
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while (entry < (struct extbl_entry *)__stop___ex_table) {
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unsigned long insn, fixup;
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insn = *ex_p++;
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fixup = *ex_p++;
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insn = (unsigned long)&entry->insn + entry->insn;
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fixup = (unsigned long)&entry->fixup + entry->fixup;
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if (insn == *ip) {
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*ip = fixup;
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