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git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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6067891b65
The early boot code contains various open-coded inline assemblies with exception handling. In order to handle possible exceptions each of them changes the program check new psw, and restores it. In order to simplify the various inline assemblies add simple exception table support: the program check handler is called with a fully populated pt_regs on the stack and may change the psw and register members. When the program check handler returns the psw and registers from pt_regs will be used to continue execution. The program check handler searches the exception table for an entry which matches the address of the program check. If such an entry is found the psw address within pt_regs on the stack is replaced with a fixup address, and execution continues at the new address. If no entry is found the psw is changed to a disabled wait psw and execution stops. Before entering the C part of the program check handler the address of the program check new psw is replaced to a minimalistic handler. This is supposed to help against program check loops. If an exception happens while in program check processing the register contents of the original exception are restored and a disabled wait psw is loaded. Acked-by: Alexander Gordeev <agordeev@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
92 lines
3 KiB
C
92 lines
3 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/kernel.h>
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#include <linux/stdarg.h>
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#include <linux/string.h>
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#include <linux/ctype.h>
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#include <asm/stacktrace.h>
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#include <asm/boot_data.h>
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#include <asm/lowcore.h>
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#include <asm/setup.h>
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#include <asm/sclp.h>
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#include <asm/uv.h>
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#include "boot.h"
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void print_stacktrace(unsigned long sp)
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{
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struct stack_info boot_stack = { STACK_TYPE_TASK, (unsigned long)_stack_start,
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(unsigned long)_stack_end };
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bool first = true;
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boot_emerg("Call Trace:\n");
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while (!(sp & 0x7) && on_stack(&boot_stack, sp, sizeof(struct stack_frame))) {
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struct stack_frame *sf = (struct stack_frame *)sp;
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if (first)
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boot_emerg("(sp:%016lx [<%016lx>] %pS)\n", sp, sf->gprs[8], (void *)sf->gprs[8]);
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else
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boot_emerg(" sp:%016lx [<%016lx>] %pS\n", sp, sf->gprs[8], (void *)sf->gprs[8]);
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if (sf->back_chain <= sp)
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break;
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sp = sf->back_chain;
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first = false;
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}
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}
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extern struct exception_table_entry __start___ex_table[];
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extern struct exception_table_entry __stop___ex_table[];
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static inline unsigned long extable_insn(const struct exception_table_entry *x)
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{
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return (unsigned long)&x->insn + x->insn;
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}
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static bool ex_handler(struct pt_regs *regs)
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{
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const struct exception_table_entry *ex;
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for (ex = __start___ex_table; ex < __stop___ex_table; ex++) {
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if (extable_insn(ex) != regs->psw.addr)
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continue;
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if (ex->type != EX_TYPE_FIXUP)
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return false;
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regs->psw.addr = extable_fixup(ex);
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return true;
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}
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return false;
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}
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void do_pgm_check(struct pt_regs *regs)
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{
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struct psw_bits *psw = &psw_bits(regs->psw);
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unsigned long *gpregs = regs->gprs;
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if (ex_handler(regs))
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return;
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if (bootdebug)
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boot_rb_dump();
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boot_emerg("Linux version %s\n", kernel_version);
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if (!is_prot_virt_guest() && early_command_line[0])
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boot_emerg("Kernel command line: %s\n", early_command_line);
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boot_emerg("Kernel fault: interruption code %04x ilc:%d\n",
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regs->int_code & 0xffff, regs->int_code >> 17);
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if (kaslr_enabled()) {
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boot_emerg("Kernel random base: %lx\n", __kaslr_offset);
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boot_emerg("Kernel random base phys: %lx\n", __kaslr_offset_phys);
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}
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boot_emerg("PSW : %016lx %016lx (%pS)\n",
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regs->psw.mask, regs->psw.addr, (void *)regs->psw.addr);
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boot_emerg(" R:%x T:%x IO:%x EX:%x Key:%x M:%x W:%x P:%x AS:%x CC:%x PM:%x RI:%x EA:%x\n",
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psw->per, psw->dat, psw->io, psw->ext, psw->key, psw->mcheck,
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psw->wait, psw->pstate, psw->as, psw->cc, psw->pm, psw->ri, psw->eaba);
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boot_emerg("GPRS: %016lx %016lx %016lx %016lx\n", gpregs[0], gpregs[1], gpregs[2], gpregs[3]);
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boot_emerg(" %016lx %016lx %016lx %016lx\n", gpregs[4], gpregs[5], gpregs[6], gpregs[7]);
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boot_emerg(" %016lx %016lx %016lx %016lx\n", gpregs[8], gpregs[9], gpregs[10], gpregs[11]);
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boot_emerg(" %016lx %016lx %016lx %016lx\n", gpregs[12], gpregs[13], gpregs[14], gpregs[15]);
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print_stacktrace(gpregs[15]);
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boot_emerg("Last Breaking-Event-Address:\n");
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boot_emerg(" [<%016lx>] %pS\n", regs->last_break, (void *)regs->last_break);
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/* Convert to disabled wait PSW */
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psw->io = 0;
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psw->ext = 0;
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psw->wait = 1;
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}
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