diff options
Diffstat (limited to 'arch/arm/lib/interrupts.c')
| -rw-r--r-- | arch/arm/lib/interrupts.c | 31 |
1 files changed, 31 insertions, 0 deletions
diff --git a/arch/arm/lib/interrupts.c b/arch/arm/lib/interrupts.c index 6dc27d1d58..9961472f69 100644 --- a/arch/arm/lib/interrupts.c +++ b/arch/arm/lib/interrupts.c @@ -22,6 +22,7 @@ #include <cpu_func.h> #include <efi_loader.h> #include <irq_func.h> +#include <semihosting.h> #include <asm/global_data.h> #include <asm/proc-armv/ptrace.h> #include <asm/ptrace.h> @@ -135,6 +136,32 @@ static inline void fixup_pc(struct pt_regs *regs, int offset) regs->ARM_pc = pc | (regs->ARM_pc & PCMASK); } +/* + * Try to "emulate" a semihosting call in the event that we don't have a + * debugger attached. + */ +static bool smh_emulate_trap(struct pt_regs *regs) +{ + if (regs->ARM_cpsr & T_BIT) { + u16 *insn = (u16 *)(regs->ARM_pc - 2); + + if (*insn != SMH_T32_SVC) + return false; + } else { + u32 *insn = (u32 *)(regs->ARM_pc - 4); + + if (*insn != SMH_A32_SVC) + return false; + } + + /* Avoid future semihosting calls */ + disable_semihosting(); + + /* Just pretend the call failed */ + regs->ARM_r0 = -1; + return true; +} + void do_undefined_instruction (struct pt_regs *pt_regs) { efi_restore_gd(); @@ -147,6 +174,10 @@ void do_undefined_instruction (struct pt_regs *pt_regs) void do_software_interrupt (struct pt_regs *pt_regs) { + if (CONFIG_IS_ENABLED(SEMIHOSTING_FALLBACK) && + smh_emulate_trap(pt_regs)) + return; + efi_restore_gd(); printf ("software interrupt\n"); fixup_pc(pt_regs, -4); |