powerpc/64: Implement soft interrupt replay in C

When local_irq_enable() finds a pending soft-masked interrupt, it
"replays" it by setting up registers like the initial interrupt entry,
then calls into the low level handler to set up an interrupt stack
frame and process the interrupt.

This is not necessary, and uses more stack than needed. The high level
interrupt handler can be called directly from C, with just pt_regs set
up on stack. This should be faster and use less stack.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200225173541.1549955-28-npiggin@gmail.com

1 files changed, 0 insertions, 47 deletions

diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
index d75df223da7c..d6536a7c2a01 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -3165,50 +3165,3 @@ doorbell_super_common_msgclr:
 	LOAD_REG_IMMEDIATE(r3, PPC_DBELL_MSGTYPE << (63-36))
 	PPC_MSGCLRP(3)
 	b 	doorbell_super_common_virt
-
-/*
- * Called from arch_local_irq_enable when an interrupt needs
- * to be resent. r3 contains 0x500, 0x900, 0xa00 or 0xe80 to indicate
- * which kind of interrupt. MSR:EE is already off. We generate a
- * stackframe like if a real interrupt had happened.
- *
- * Note: While MSR:EE is off, we need to make sure that _MSR
- * in the generated frame has EE set to 1 or the exception
- * handler will not properly re-enable them.
- *
- * Note that we don't specify LR as the NIP (return address) for
- * the interrupt because that would unbalance the return branch
- * predictor.
- */
-_GLOBAL(__replay_interrupt)
-	/* We are going to jump to the exception common code which
-	 * will retrieve various register values from the PACA which
-	 * we don't give a damn about, so we don't bother storing them.
-	 */
-	mfmsr	r12
-	LOAD_REG_ADDR(r11, replay_interrupt_return)
-	mfcr	r9
-	ori	r12,r12,MSR_EE
-	cmpwi	r3,0x900
-	beq	decrementer_common_virt
-	cmpwi	r3,0x500
-BEGIN_FTR_SECTION
-	beq	h_virt_irq_common_virt
-FTR_SECTION_ELSE
-	beq	hardware_interrupt_common_virt
-ALT_FTR_SECTION_END_IFSET(CPU_FTR_HVMODE | CPU_FTR_ARCH_300)
-	cmpwi	r3,0xf00
-	beq	performance_monitor_common_virt
-BEGIN_FTR_SECTION
-	cmpwi	r3,0xa00
-	beq	h_doorbell_common_msgclr
-	cmpwi	r3,0xe60
-	beq	hmi_exception_common_virt
-FTR_SECTION_ELSE
-	cmpwi	r3,0xa00
-	beq	doorbell_super_common_msgclr
-ALT_FTR_SECTION_END_IFSET(CPU_FTR_HVMODE)
-replay_interrupt_return:
-	blr
-
-_ASM_NOKPROBE_SYMBOL(__replay_interrupt)