diff options
Diffstat (limited to 'arch/ia64/kernel/brl_emu.c')
| -rw-r--r-- | arch/ia64/kernel/brl_emu.c | 217 |
1 files changed, 217 insertions, 0 deletions
diff --git a/arch/ia64/kernel/brl_emu.c b/arch/ia64/kernel/brl_emu.c new file mode 100644 index 0000000000..782c481d70 --- /dev/null +++ b/arch/ia64/kernel/brl_emu.c @@ -0,0 +1,217 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Emulation of the "brl" instruction for IA64 processors that + * don't support it in hardware. + * Author: Stephan Zeisset, Intel Corp. <Stephan.Zeisset@intel.com> + * + * 02/22/02 D. Mosberger Clear si_flgs, si_isr, and si_imm to avoid + * leaking kernel bits. + */ + +#include <linux/kernel.h> +#include <linux/sched/signal.h> +#include <linux/uaccess.h> +#include <asm/processor.h> + +extern char ia64_set_b1, ia64_set_b2, ia64_set_b3, ia64_set_b4, ia64_set_b5; + +struct illegal_op_return { + unsigned long fkt, arg1, arg2, arg3; +}; + +/* + * The unimplemented bits of a virtual address must be set + * to the value of the most significant implemented bit. + * unimpl_va_mask includes all unimplemented bits and + * the most significant implemented bit, so the result + * of an and operation with the mask must be all 0's + * or all 1's for the address to be valid. + */ +#define unimplemented_virtual_address(va) ( \ + ((va) & local_cpu_data->unimpl_va_mask) != 0 && \ + ((va) & local_cpu_data->unimpl_va_mask) != local_cpu_data->unimpl_va_mask \ +) + +/* + * The unimplemented bits of a physical address must be 0. + * unimpl_pa_mask includes all unimplemented bits, so the result + * of an and operation with the mask must be all 0's for the + * address to be valid. + */ +#define unimplemented_physical_address(pa) ( \ + ((pa) & local_cpu_data->unimpl_pa_mask) != 0 \ +) + +/* + * Handle an illegal operation fault that was caused by an + * unimplemented "brl" instruction. + * If we are not successful (e.g because the illegal operation + * wasn't caused by a "brl" after all), we return -1. + * If we are successful, we return either 0 or the address + * of a "fixup" function for manipulating preserved register + * state. + */ + +struct illegal_op_return +ia64_emulate_brl (struct pt_regs *regs, unsigned long ar_ec) +{ + unsigned long bundle[2]; + unsigned long opcode, btype, qp, offset, cpl; + unsigned long next_ip; + struct illegal_op_return rv; + long tmp_taken, unimplemented_address; + + rv.fkt = (unsigned long) -1; + + /* + * Decode the instruction bundle. + */ + + if (copy_from_user(bundle, (void *) (regs->cr_iip), sizeof(bundle))) + return rv; + + next_ip = (unsigned long) regs->cr_iip + 16; + + /* "brl" must be in slot 2. */ + if (ia64_psr(regs)->ri != 1) return rv; + + /* Must be "mlx" template */ + if ((bundle[0] & 0x1e) != 0x4) return rv; + + opcode = (bundle[1] >> 60); + btype = ((bundle[1] >> 29) & 0x7); + qp = ((bundle[1] >> 23) & 0x3f); + offset = ((bundle[1] & 0x0800000000000000L) << 4) + | ((bundle[1] & 0x00fffff000000000L) >> 32) + | ((bundle[1] & 0x00000000007fffffL) << 40) + | ((bundle[0] & 0xffff000000000000L) >> 24); + + tmp_taken = regs->pr & (1L << qp); + + switch(opcode) { + + case 0xC: + /* + * Long Branch. + */ + if (btype != 0) return rv; + rv.fkt = 0; + if (!(tmp_taken)) { + /* + * Qualifying predicate is 0. + * Skip instruction. + */ + regs->cr_iip = next_ip; + ia64_psr(regs)->ri = 0; + return rv; + } + break; + + case 0xD: + /* + * Long Call. + */ + rv.fkt = 0; + if (!(tmp_taken)) { + /* + * Qualifying predicate is 0. + * Skip instruction. + */ + regs->cr_iip = next_ip; + ia64_psr(regs)->ri = 0; + return rv; + } + + /* + * BR[btype] = IP+16 + */ + switch(btype) { + case 0: + regs->b0 = next_ip; + break; + case 1: + rv.fkt = (unsigned long) &ia64_set_b1; + break; + case 2: + rv.fkt = (unsigned long) &ia64_set_b2; + break; + case 3: + rv.fkt = (unsigned long) &ia64_set_b3; + break; + case 4: + rv.fkt = (unsigned long) &ia64_set_b4; + break; + case 5: + rv.fkt = (unsigned long) &ia64_set_b5; + break; + case 6: + regs->b6 = next_ip; + break; + case 7: + regs->b7 = next_ip; + break; + } + rv.arg1 = next_ip; + + /* + * AR[PFS].pfm = CFM + * AR[PFS].pec = AR[EC] + * AR[PFS].ppl = PSR.cpl + */ + cpl = ia64_psr(regs)->cpl; + regs->ar_pfs = ((regs->cr_ifs & 0x3fffffffff) + | (ar_ec << 52) | (cpl << 62)); + + /* + * CFM.sof -= CFM.sol + * CFM.sol = 0 + * CFM.sor = 0 + * CFM.rrb.gr = 0 + * CFM.rrb.fr = 0 + * CFM.rrb.pr = 0 + */ + regs->cr_ifs = ((regs->cr_ifs & 0xffffffc00000007f) + - ((regs->cr_ifs >> 7) & 0x7f)); + + break; + + default: + /* + * Unknown opcode. + */ + return rv; + + } + + regs->cr_iip += offset; + ia64_psr(regs)->ri = 0; + + if (ia64_psr(regs)->it == 0) + unimplemented_address = unimplemented_physical_address(regs->cr_iip); + else + unimplemented_address = unimplemented_virtual_address(regs->cr_iip); + + if (unimplemented_address) { + /* + * The target address contains unimplemented bits. + */ + printk(KERN_DEBUG "Woah! Unimplemented Instruction Address Trap!\n"); + force_sig_fault(SIGILL, ILL_BADIADDR, (void __user *)NULL, + 0, 0, 0); + } else if (ia64_psr(regs)->tb) { + /* + * Branch Tracing is enabled. + * Force a taken branch signal. + */ + force_sig_fault(SIGTRAP, TRAP_BRANCH, (void __user *)NULL, + 0, 0, 0); + } else if (ia64_psr(regs)->ss) { + /* + * Single Step is enabled. + * Force a trace signal. + */ + force_sig_fault(SIGTRAP, TRAP_TRACE, (void __user *)NULL, + 0, 0, 0); + } + return rv; +} |