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-rw-r--r--arch/powerpc/kernel/exceptions-64s.S150
1 files changed, 143 insertions, 7 deletions
diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
index 446e54c3f71e..f7d748b88705 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -508,8 +508,24 @@ DEFINE_FIXED_SYMBOL(\name\()_common_real)
.macro __GEN_COMMON_BODY name
.if IMASK
+ .if ! ISTACK
+ .error "No support for masked interrupt to use custom stack"
+ .endif
+
+ /* If coming from user, skip soft-mask tests. */
+ andi. r10,r12,MSR_PR
+ bne 2f
+
+ /* Kernel code running below __end_interrupts is implicitly
+ * soft-masked */
+ LOAD_HANDLER(r10, __end_interrupts)
+ cmpld r11,r10
+ li r10,IMASK
+ blt- 1f
+
+ /* Test the soft mask state against our interrupt's bit */
lbz r10,PACAIRQSOFTMASK(r13)
- andi. r10,r10,IMASK
+1: andi. r10,r10,IMASK
/* Associate vector numbers with bits in paca->irq_happened */
.if IVEC == 0x500 || IVEC == 0xea0
li r10,PACA_IRQ_EE
@@ -540,7 +556,7 @@ DEFINE_FIXED_SYMBOL(\name\()_common_real)
.if ISTACK
andi. r10,r12,MSR_PR /* See if coming from user */
- mr r10,r1 /* Save r1 */
+2: mr r10,r1 /* Save r1 */
subi r1,r1,INT_FRAME_SIZE /* alloc frame on kernel stack */
beq- 100f
ld r1,PACAKSAVE(r13) /* kernel stack to use */
@@ -740,6 +756,9 @@ END_FTR_SECTION_IFSET(CPU_FTR_CAN_NAP)
* guarantee they will be delivered virtually. Some conditions (see the ISA)
* cause exceptions to be delivered in real mode.
*
+ * The scv instructions are a special case. They get a 0x3000 offset applied.
+ * scv exceptions have unique reentrancy properties, see below.
+ *
* It's impossible to receive interrupts below 0x300 via AIL.
*
* KVM: None of the virtual exceptions are from the guest. Anything that
@@ -749,8 +768,8 @@ END_FTR_SECTION_IFSET(CPU_FTR_CAN_NAP)
* We layout physical memory as follows:
* 0x0000 - 0x00ff : Secondary processor spin code
* 0x0100 - 0x18ff : Real mode pSeries interrupt vectors
- * 0x1900 - 0x3fff : Real mode trampolines
- * 0x4000 - 0x58ff : Relon (IR=1,DR=1) mode pSeries interrupt vectors
+ * 0x1900 - 0x2fff : Real mode trampolines
+ * 0x3000 - 0x58ff : Relon (IR=1,DR=1) mode pSeries interrupt vectors
* 0x5900 - 0x6fff : Relon mode trampolines
* 0x7000 - 0x7fff : FWNMI data area
* 0x8000 - .... : Common interrupt handlers, remaining early
@@ -761,8 +780,8 @@ END_FTR_SECTION_IFSET(CPU_FTR_CAN_NAP)
* vectors there.
*/
OPEN_FIXED_SECTION(real_vectors, 0x0100, 0x1900)
-OPEN_FIXED_SECTION(real_trampolines, 0x1900, 0x4000)
-OPEN_FIXED_SECTION(virt_vectors, 0x4000, 0x5900)
+OPEN_FIXED_SECTION(real_trampolines, 0x1900, 0x3000)
+OPEN_FIXED_SECTION(virt_vectors, 0x3000, 0x5900)
OPEN_FIXED_SECTION(virt_trampolines, 0x5900, 0x7000)
#ifdef CONFIG_PPC_POWERNV
@@ -798,6 +817,77 @@ USE_FIXED_SECTION(real_vectors)
.globl __start_interrupts
__start_interrupts:
+/**
+ * Interrupt 0x3000 - System Call Vectored Interrupt (syscall).
+ * This is a synchronous interrupt invoked with the "scv" instruction. The
+ * system call does not alter the HV bit, so it is directed to the OS.
+ *
+ * Handling:
+ * scv instructions enter the kernel without changing EE, RI, ME, or HV.
+ * In particular, this means we can take a maskable interrupt at any point
+ * in the scv handler, which is unlike any other interrupt. This is solved
+ * by treating the instruction addresses below __end_interrupts as being
+ * soft-masked.
+ *
+ * AIL-0 mode scv exceptions go to 0x17000-0x17fff, but we set AIL-3 and
+ * ensure scv is never executed with relocation off, which means AIL-0
+ * should never happen.
+ *
+ * Before leaving the below __end_interrupts text, at least of the following
+ * must be true:
+ * - MSR[PR]=1 (i.e., return to userspace)
+ * - MSR_EE|MSR_RI is set (no reentrant exceptions)
+ * - Standard kernel environment is set up (stack, paca, etc)
+ *
+ * Call convention:
+ *
+ * syscall register convention is in Documentation/powerpc/syscall64-abi.rst
+ */
+EXC_VIRT_BEGIN(system_call_vectored, 0x3000, 0x1000)
+ /* SCV 0 */
+ mr r9,r13
+ GET_PACA(r13)
+ mflr r11
+ mfctr r12
+ li r10,IRQS_ALL_DISABLED
+ stb r10,PACAIRQSOFTMASK(r13)
+#ifdef CONFIG_RELOCATABLE
+ b system_call_vectored_tramp
+#else
+ b system_call_vectored_common
+#endif
+ nop
+
+ /* SCV 1 - 127 */
+ .rept 127
+ mr r9,r13
+ GET_PACA(r13)
+ mflr r11
+ mfctr r12
+ li r10,IRQS_ALL_DISABLED
+ stb r10,PACAIRQSOFTMASK(r13)
+ li r0,-1 /* cause failure */
+#ifdef CONFIG_RELOCATABLE
+ b system_call_vectored_sigill_tramp
+#else
+ b system_call_vectored_sigill
+#endif
+ .endr
+EXC_VIRT_END(system_call_vectored, 0x3000, 0x1000)
+
+#ifdef CONFIG_RELOCATABLE
+TRAMP_VIRT_BEGIN(system_call_vectored_tramp)
+ __LOAD_HANDLER(r10, system_call_vectored_common)
+ mtctr r10
+ bctr
+
+TRAMP_VIRT_BEGIN(system_call_vectored_sigill_tramp)
+ __LOAD_HANDLER(r10, system_call_vectored_sigill)
+ mtctr r10
+ bctr
+#endif
+
+
/* No virt vectors corresponding with 0x0..0x100 */
EXC_VIRT_NONE(0x4000, 0x100)
@@ -2838,7 +2928,8 @@ masked_interrupt:
ld r10,PACA_EXGEN+EX_R10(r13)
ld r11,PACA_EXGEN+EX_R11(r13)
ld r12,PACA_EXGEN+EX_R12(r13)
- /* returns to kernel where r13 must be set up, so don't restore it */
+ ld r13,PACA_EXGEN+EX_R13(r13)
+ /* May return to masked low address where r13 is not set up */
.if \hsrr
HRFI_TO_KERNEL
.else
@@ -2946,6 +3037,47 @@ TRAMP_REAL_BEGIN(hrfi_flush_fallback)
GET_SCRATCH0(r13);
hrfid
+TRAMP_REAL_BEGIN(rfscv_flush_fallback)
+ /* system call volatile */
+ mr r7,r13
+ GET_PACA(r13);
+ mr r8,r1
+ ld r1,PACAKSAVE(r13)
+ mfctr r9
+ ld r10,PACA_RFI_FLUSH_FALLBACK_AREA(r13)
+ ld r11,PACA_L1D_FLUSH_SIZE(r13)
+ srdi r11,r11,(7 + 3) /* 128 byte lines, unrolled 8x */
+ mtctr r11
+ DCBT_BOOK3S_STOP_ALL_STREAM_IDS(r11) /* Stop prefetch streams */
+
+ /* order ld/st prior to dcbt stop all streams with flushing */
+ sync
+
+ /*
+ * The load adresses are at staggered offsets within cachelines,
+ * which suits some pipelines better (on others it should not
+ * hurt).
+ */
+1:
+ ld r11,(0x80 + 8)*0(r10)
+ ld r11,(0x80 + 8)*1(r10)
+ ld r11,(0x80 + 8)*2(r10)
+ ld r11,(0x80 + 8)*3(r10)
+ ld r11,(0x80 + 8)*4(r10)
+ ld r11,(0x80 + 8)*5(r10)
+ ld r11,(0x80 + 8)*6(r10)
+ ld r11,(0x80 + 8)*7(r10)
+ addi r10,r10,0x80*8
+ bdnz 1b
+
+ mtctr r9
+ li r9,0
+ li r10,0
+ li r11,0
+ mr r1,r8
+ mr r13,r7
+ RFSCV
+
USE_TEXT_SECTION()
MASKED_INTERRUPT
MASKED_INTERRUPT hsrr=1
@@ -2997,6 +3129,10 @@ EXC_COMMON_BEGIN(ppc64_runlatch_on_trampoline)
USE_FIXED_SECTION(virt_trampolines)
/*
+ * All code below __end_interrupts is treated as soft-masked. If
+ * any code runs here with MSR[EE]=1, it must then cope with pending
+ * soft interrupt being raised (i.e., by ensuring it is replayed).
+ *
* The __end_interrupts marker must be past the out-of-line (OOL)
* handlers, so that they are copied to real address 0x100 when running
* a relocatable kernel. This ensures they can be reached from the short