This is a work-in-progress patch to avoid unneccesary saving of floating point regs when entering syscalls (it still generates segfaults...!). The compiler option -mdisable-fpregs takes care that we don't use fp regs in kernel code by accident. Signed-off-by: Helge Deller <deller@xxxxxx> diff --git a/arch/parisc/kernel/entry.S b/arch/parisc/kernel/entry.S index e8f07dd..810769b 100644 --- a/arch/parisc/kernel/entry.S +++ b/arch/parisc/kernel/entry.S @@ -785,9 +785,13 @@ ENDPROC(ret_from_kernel_thread) ENTRY(_switch_to) STREG %r2, -RP_OFFSET(%r30) - callee_save_float callee_save + /* TODO: we could check TASK_FLAGS and only save the fpregs when + * switching away from a userspace task. */ + ldo TASK_PT_FR0(%r26), %r1 /* save fpregs for task switch */ + save_fp %r1 + load32 _switch_to_ret, %r2 STREG %r2, TASK_PT_KPC(%r26) @@ -795,6 +799,12 @@ ENTRY(_switch_to) STREG %r30, TASK_PT_KSP(%r26) LDREG TASK_PT_KSP(%r25), %r30 + + /* TODO: we could check TASK_FLAGS and restore the fpregs only when + * we return to a userspace task. */ + ldo TASK_PT_FR31(%r25),%r1 /* reload fpregs */ + rest_fp %r1 + LDREG TASK_THREAD_INFO(%r25), %r25 bv %r0(%r2) mtctl %r25,%cr30 @@ -802,7 +812,6 @@ ENTRY(_switch_to) _switch_to_ret: mtctl %r0, %cr0 /* Needed for single stepping */ callee_rest - callee_rest_float LDREG -RP_OFFSET(%r30), %r2 bv %r0(%r2) @@ -913,8 +922,6 @@ intr_check_sig: intr_restore: copy %r16,%r29 - ldo PT_FR31(%r29),%r1 - rest_fp %r1 rest_general %r29 /* inverse of virt_map */ @@ -1013,9 +1020,6 @@ intr_extint: virt_map save_general %r29 - ldo PT_FR0(%r29), %r24 - save_fp %r24 - loadgp copy %r29, %r26 /* arg0 is pt_regs */ @@ -1094,9 +1098,6 @@ skip_save_ior: virt_map save_general %r29 - ldo PT_FR0(%r29), %r25 - save_fp %r25 - loadgp copy %r29, %r25 /* arg1 is pt_regs */ @@ -1856,9 +1857,6 @@ syscall_restore: and,COND(=) %r19,%r2,%r0 b,n syscall_restore_rfi - ldo TASK_PT_FR31(%r1),%r19 /* reload fpregs */ - rest_fp %r19 - LDREG TASK_PT_SAR(%r1),%r19 /* restore SAR */ mtsar %r19 diff --git a/arch/parisc/kernel/syscall.S b/arch/parisc/kernel/syscall.S index a63bb179..89163e7 100644 --- a/arch/parisc/kernel/syscall.S +++ b/arch/parisc/kernel/syscall.S @@ -184,9 +184,6 @@ linux_gateway_entry: STREG %r29, TASK_PT_GR29(%r1) /* return value 1 */ STREG %r31, TASK_PT_GR31(%r1) /* preserve syscall return ptr */ - ldo TASK_PT_FR0(%r1), %r27 /* save fpregs from the kernel */ - save_fp %r27 /* or potential task switch */ - mfctl %cr11, %r27 /* i.e. SAR */ STREG %r27, TASK_PT_SAR(%r1) @@ -310,6 +307,8 @@ tracesys: STREG %r16,PT_GR16(%r2) STREG %r17,PT_GR17(%r2) STREG %r18,PT_GR18(%r2) + ldo PT_FR0(%r2), %r1 /* save fpregs */ + save_fp %r1 /* Finished saving things for the debugger */ copy %r2,%r26 -- To unsubscribe from this list: send the line "unsubscribe linux-parisc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
