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-rw-r--r--arch/tile/kernel/intvec_64.S305
1 files changed, 275 insertions, 30 deletions
diff --git a/arch/tile/kernel/intvec_64.S b/arch/tile/kernel/intvec_64.S
index 85d48395702..ec755d3f373 100644
--- a/arch/tile/kernel/intvec_64.S
+++ b/arch/tile/kernel/intvec_64.S
@@ -17,25 +17,33 @@
#include <linux/linkage.h>
#include <linux/errno.h>
#include <linux/unistd.h>
+#include <linux/init.h>
#include <asm/ptrace.h>
#include <asm/thread_info.h>
#include <asm/irqflags.h>
#include <asm/asm-offsets.h>
#include <asm/types.h>
+#include <asm/traps.h>
#include <asm/signal.h>
#include <hv/hypervisor.h>
#include <arch/abi.h>
#include <arch/interrupts.h>
#include <arch/spr_def.h>
-#ifdef CONFIG_PREEMPT
-# error "No support for kernel preemption currently"
-#endif
-
#define PTREGS_PTR(reg, ptreg) addli reg, sp, C_ABI_SAVE_AREA_SIZE + (ptreg)
#define PTREGS_OFFSET_SYSCALL PTREGS_OFFSET_REG(TREG_SYSCALL_NR)
+#if CONFIG_KERNEL_PL == 1 || CONFIG_KERNEL_PL == 2
+/*
+ * Set "result" non-zero if ex1 holds the PL of the kernel
+ * (with or without ICS being set). Note this works only
+ * because we never find the PL at level 3.
+ */
+# define IS_KERNEL_EX1(result, ex1) andi result, ex1, CONFIG_KERNEL_PL
+#else
+# error Recode IS_KERNEL_EX1 for CONFIG_KERNEL_PL
+#endif
.macro push_reg reg, ptr=sp, delta=-8
{
@@ -98,6 +106,185 @@
}
.endm
+ /*
+ * Unalign data exception fast handling: In order to handle
+ * unaligned data access, a fast JIT version is generated and stored
+ * in a specific area in user space. We first need to do a quick poke
+ * to see if the JIT is available. We use certain bits in the fault
+ * PC (3 to 9 is used for 16KB page size) as index to address the JIT
+ * code area. The first 64bit word is the fault PC, and the 2nd one is
+ * the fault bundle itself. If these 2 words both match, then we
+ * directly "iret" to JIT code. If not, a slow path is invoked to
+ * generate new JIT code. Note: the current JIT code WILL be
+ * overwritten if it existed. So, ideally we can handle 128 unalign
+ * fixups via JIT. For lookup efficiency and to effectively support
+ * tight loops with multiple unaligned reference, a simple
+ * direct-mapped cache is used.
+ *
+ * SPR_EX_CONTEXT_K_0 is modified to return to JIT code.
+ * SPR_EX_CONTEXT_K_1 has ICS set.
+ * SPR_EX_CONTEXT_0_0 is setup to user program's next PC.
+ * SPR_EX_CONTEXT_0_1 = 0.
+ */
+ .macro int_hand_unalign_fast vecnum, vecname
+ .org (\vecnum << 8)
+intvec_\vecname:
+ /* Put r3 in SPR_SYSTEM_SAVE_K_1. */
+ mtspr SPR_SYSTEM_SAVE_K_1, r3
+
+ mfspr r3, SPR_EX_CONTEXT_K_1
+ /*
+ * Examine if exception comes from user without ICS set.
+ * If not, just go directly to the slow path.
+ */
+ bnez r3, hand_unalign_slow_nonuser
+
+ mfspr r3, SPR_SYSTEM_SAVE_K_0
+
+ /* Get &thread_info->unalign_jit_tmp[0] in r3. */
+ bfexts r3, r3, 0, CPU_SHIFT-1
+ mm r3, zero, LOG2_THREAD_SIZE, 63
+ addli r3, r3, THREAD_INFO_UNALIGN_JIT_TMP_OFFSET
+
+ /*
+ * Save r0, r1, r2 into thread_info array r3 points to
+ * from low to high memory in order.
+ */
+ st_add r3, r0, 8
+ st_add r3, r1, 8
+ {
+ st_add r3, r2, 8
+ andi r2, sp, 7
+ }
+
+ /* Save stored r3 value so we can revert it on a page fault. */
+ mfspr r1, SPR_SYSTEM_SAVE_K_1
+ st r3, r1
+
+ {
+ /* Generate a SIGBUS if sp is not 8-byte aligned. */
+ bnez r2, hand_unalign_slow_badsp
+ }
+
+ /*
+ * Get the thread_info in r0; load r1 with pc. Set the low bit of sp
+ * as an indicator to the page fault code in case we fault.
+ */
+ {
+ ori sp, sp, 1
+ mfspr r1, SPR_EX_CONTEXT_K_0
+ }
+
+ /* Add the jit_info offset in thread_info; extract r1 [3:9] into r2. */
+ {
+ addli r0, r3, THREAD_INFO_UNALIGN_JIT_BASE_OFFSET - \
+ (THREAD_INFO_UNALIGN_JIT_TMP_OFFSET + (3 * 8))
+ bfextu r2, r1, 3, (2 + PAGE_SHIFT - UNALIGN_JIT_SHIFT)
+ }
+
+ /* Load the jit_info; multiply r2 by 128. */
+ {
+ ld r0, r0
+ shli r2, r2, UNALIGN_JIT_SHIFT
+ }
+
+ /*
+ * If r0 is NULL, the JIT page is not mapped, so go to slow path;
+ * add offset r2 to r0 at the same time.
+ */
+ {
+ beqz r0, hand_unalign_slow
+ add r2, r0, r2
+ }
+
+ /*
+ * We are loading from userspace (both the JIT info PC and
+ * instruction word, and the instruction word we executed)
+ * and since either could fault while holding the interrupt
+ * critical section, we must tag this region and check it in
+ * do_page_fault() to handle it properly.
+ */
+ENTRY(__start_unalign_asm_code)
+
+ /* Load first word of JIT in r0 and increment r2 by 8. */
+ ld_add r0, r2, 8
+
+ /*
+ * Compare the PC with the 1st word in JIT; load the fault bundle
+ * into r1.
+ */
+ {
+ cmpeq r0, r0, r1
+ ld r1, r1
+ }
+
+ /* Go to slow path if PC doesn't match. */
+ beqz r0, hand_unalign_slow
+
+ /*
+ * Load the 2nd word of JIT, which is supposed to be the fault
+ * bundle for a cache hit. Increment r2; after this bundle r2 will
+ * point to the potential start of the JIT code we want to run.
+ */
+ ld_add r0, r2, 8
+
+ /* No further accesses to userspace are done after this point. */
+ENTRY(__end_unalign_asm_code)
+
+ /* Compare the real bundle with what is saved in the JIT area. */
+ {
+ cmpeq r0, r1, r0
+ mtspr SPR_EX_CONTEXT_0_1, zero
+ }
+
+ /* Go to slow path if the fault bundle does not match. */
+ beqz r0, hand_unalign_slow
+
+ /*
+ * A cache hit is found.
+ * r2 points to start of JIT code (3rd word).
+ * r0 is the fault pc.
+ * r1 is the fault bundle.
+ * Reset the low bit of sp.
+ */
+ {
+ mfspr r0, SPR_EX_CONTEXT_K_0
+ andi sp, sp, ~1
+ }
+
+ /* Write r2 into EX_CONTEXT_K_0 and increment PC. */
+ {
+ mtspr SPR_EX_CONTEXT_K_0, r2
+ addi r0, r0, 8
+ }
+
+ /*
+ * Set ICS on kernel EX_CONTEXT_K_1 in order to "iret" to
+ * user with ICS set. This way, if the JIT fixup causes another
+ * unalign exception (which shouldn't be possible) the user
+ * process will be terminated with SIGBUS. Also, our fixup will
+ * run without interleaving with external interrupts.
+ * Each fixup is at most 14 bundles, so it won't hold ICS for long.
+ */
+ {
+ movei r1, PL_ICS_EX1(USER_PL, 1)
+ mtspr SPR_EX_CONTEXT_0_0, r0
+ }
+
+ {
+ mtspr SPR_EX_CONTEXT_K_1, r1
+ addi r3, r3, -(3 * 8)
+ }
+
+ /* Restore r0..r3. */
+ ld_add r0, r3, 8
+ ld_add r1, r3, 8
+ ld_add r2, r3, 8
+ ld r3, r3
+
+ iret
+ ENDPROC(intvec_\vecname)
+ .endm
#ifdef __COLLECT_LINKER_FEEDBACK__
.pushsection .text.intvec_feedback,"ax"
@@ -118,15 +305,21 @@ intvec_feedback:
* The "processing" argument specifies the code for processing
* the interrupt. Defaults to "handle_interrupt".
*/
- .macro int_hand vecnum, vecname, c_routine, processing=handle_interrupt
- .org (\vecnum << 8)
+ .macro __int_hand vecnum, vecname, c_routine,processing=handle_interrupt
intvec_\vecname:
/* Temporarily save a register so we have somewhere to work. */
mtspr SPR_SYSTEM_SAVE_K_1, r0
mfspr r0, SPR_EX_CONTEXT_K_1
- andi r0, r0, SPR_EX_CONTEXT_1_1__PL_MASK /* mask off ICS */
+ /*
+ * The unalign data fastpath code sets the low bit in sp to
+ * force us to reset it here on fault.
+ */
+ {
+ blbs sp, 2f
+ IS_KERNEL_EX1(r0, r0)
+ }
.ifc \vecnum, INT_DOUBLE_FAULT
/*
@@ -176,15 +369,15 @@ intvec_\vecname:
}
.endif
-
+2:
/*
- * SYSTEM_SAVE_K_0 holds the cpu number in the low bits, and
- * the current stack top in the higher bits. So we recover
- * our stack top by just masking off the low bits, then
+ * SYSTEM_SAVE_K_0 holds the cpu number in the high bits, and
+ * the current stack top in the lower bits. So we recover
+ * our starting stack value by sign-extending the low bits, then
* point sp at the top aligned address on the actual stack page.
*/
mfspr r0, SPR_SYSTEM_SAVE_K_0
- mm r0, zero, LOG2_THREAD_SIZE, 63
+ bfexts r0, r0, 0, CPU_SHIFT-1
0:
/*
@@ -206,6 +399,9 @@ intvec_\vecname:
* cache line 1: r6...r13
* cache line 0: 2 x frame, r0..r5
*/
+#if STACK_TOP_DELTA != 64
+#error STACK_TOP_DELTA must be 64 for assumptions here and in task_pt_regs()
+#endif
andi r0, r0, -64
/*
@@ -305,7 +501,7 @@ intvec_\vecname:
mfspr r3, SPR_SYSTEM_SAVE_K_2 /* info about page fault */
.else
.ifc \vecnum, INT_ILL_TRANS
- mfspr r2, ILL_TRANS_REASON
+ mfspr r2, ILL_VA_PC
.else
.ifc \vecnum, INT_DOUBLE_FAULT
mfspr r2, SPR_SYSTEM_SAVE_K_2 /* double fault info from HV */
@@ -315,12 +511,10 @@ intvec_\vecname:
.else
.ifc \c_routine, op_handle_perf_interrupt
mfspr r2, PERF_COUNT_STS
-#if CHIP_HAS_AUX_PERF_COUNTERS()
.else
.ifc \c_routine, op_handle_aux_perf_interrupt
mfspr r2, AUX_PERF_COUNT_STS
.endif
-#endif
.endif
.endif
.endif
@@ -339,7 +533,7 @@ intvec_\vecname:
#ifdef __COLLECT_LINKER_FEEDBACK__
.pushsection .text.intvec_feedback,"ax"
.org (\vecnum << 5)
- FEEDBACK_ENTER_EXPLICIT(intvec_\vecname, .intrpt1, 1 << 8)
+ FEEDBACK_ENTER_EXPLICIT(intvec_\vecname, .intrpt, 1 << 8)
jrp lr
.popsection
#endif
@@ -455,11 +649,12 @@ intvec_\vecname:
/*
* If we will be returning to the kernel, we will need to
* reset the interrupt masks to the state they had before.
- * Set DISABLE_IRQ in flags iff we came from PL1 with irqs disabled.
+ * Set DISABLE_IRQ in flags iff we came from kernel pl with
+ * irqs disabled.
*/
mfspr r32, SPR_EX_CONTEXT_K_1
{
- andi r32, r32, SPR_EX_CONTEXT_1_1__PL_MASK /* mask off ICS */
+ IS_KERNEL_EX1(r22, r22)
PTREGS_PTR(r21, PTREGS_OFFSET_FLAGS)
}
beqzt r32, 1f /* zero if from user space */
@@ -503,7 +698,7 @@ intvec_\vecname:
}
{
shl16insli r21, r21, hw1(__per_cpu_offset)
- bfextu r20, r20, 0, LOG2_THREAD_SIZE-1
+ bfextu r20, r20, CPU_SHIFT, 63
}
shl16insli r21, r21, hw0(__per_cpu_offset)
shl3add r20, r20, r21
@@ -585,7 +780,7 @@ intvec_\vecname:
.macro dc_dispatch vecnum, vecname
.org (\vecnum << 8)
intvec_\vecname:
- j hv_downcall_dispatch
+ j _hv_downcall_dispatch
ENDPROC(intvec_\vecname)
.endm
@@ -626,14 +821,36 @@ STD_ENTRY(interrupt_return)
PTREGS_PTR(r29, PTREGS_OFFSET_EX1)
}
ld r29, r29
- andi r29, r29, SPR_EX_CONTEXT_1_1__PL_MASK /* mask off ICS */
+ IS_KERNEL_EX1(r29, r29)
{
beqzt r29, .Lresume_userspace
- PTREGS_PTR(r29, PTREGS_OFFSET_PC)
+ move r29, sp
+ }
+
+#ifdef CONFIG_PREEMPT
+ /* Returning to kernel space. Check if we need preemption. */
+ EXTRACT_THREAD_INFO(r29)
+ addli r28, r29, THREAD_INFO_FLAGS_OFFSET
+ {
+ ld r28, r28
+ addli r29, r29, THREAD_INFO_PREEMPT_COUNT_OFFSET
+ }
+ {
+ andi r28, r28, _TIF_NEED_RESCHED
+ ld4s r29, r29
}
+ beqzt r28, 1f
+ bnez r29, 1f
+ jal preempt_schedule_irq
+ FEEDBACK_REENTER(interrupt_return)
+1:
+#endif
/* If we're resuming to _cpu_idle_nap, bump PC forward by 8. */
- moveli r27, hw2_last(_cpu_idle_nap)
+ {
+ moveli r27, hw2_last(_cpu_idle_nap)
+ PTREGS_PTR(r29, PTREGS_OFFSET_PC)
+ }
{
ld r28, r29
shl16insli r27, r27, hw1(_cpu_idle_nap)
@@ -728,7 +945,7 @@ STD_ENTRY(interrupt_return)
PTREGS_PTR(r32, PTREGS_OFFSET_FLAGS)
}
{
- andi r0, r0, SPR_EX_CONTEXT_1_1__PL_MASK
+ IS_KERNEL_EX1(r0, r0)
ld r32, r32
}
bnez r0, 1f
@@ -799,7 +1016,7 @@ STD_ENTRY(interrupt_return)
pop_reg r21, sp, PTREGS_OFFSET_REG(31) - PTREGS_OFFSET_PC
{
mtspr SPR_EX_CONTEXT_K_1, lr
- andi lr, lr, SPR_EX_CONTEXT_1_1__PL_MASK /* mask off ICS */
+ IS_KERNEL_EX1(lr, lr)
}
{
mtspr SPR_EX_CONTEXT_K_0, r21
@@ -1223,10 +1440,31 @@ STD_ENTRY(_sys_clone)
j sys_clone
STD_ENDPROC(_sys_clone)
-/* The single-step support may need to read all the registers. */
+ /*
+ * Recover r3, r2, r1 and r0 here saved by unalign fast vector.
+ * The vector area limit is 32 bundles, so we handle the reload here.
+ * r0, r1, r2 are in thread_info from low to high memory in order.
+ * r3 points to location the original r3 was saved.
+ * We put this code in the __HEAD section so it can be reached
+ * via a conditional branch from the fast path.
+ */
+ __HEAD
+hand_unalign_slow:
+ andi sp, sp, ~1
+hand_unalign_slow_badsp:
+ addi r3, r3, -(3 * 8)
+ ld_add r0, r3, 8
+ ld_add r1, r3, 8
+ ld r2, r3
+hand_unalign_slow_nonuser:
+ mfspr r3, SPR_SYSTEM_SAVE_K_1
+ __int_hand INT_UNALIGN_DATA, UNALIGN_DATA_SLOW, int_unalign
+
+/* The unaligned data support needs to read all the registers. */
int_unalign:
push_extra_callee_saves r0
- j do_trap
+ j do_unaligned
+ENDPROC(hand_unalign_slow)
/* Fill the return address stack with nonzero entries. */
STD_ENTRY(fill_ra_stack)
@@ -1240,8 +1478,15 @@ STD_ENTRY(fill_ra_stack)
4: jrp r0
STD_ENDPROC(fill_ra_stack)
-/* Include .intrpt1 array of interrupt vectors */
- .section ".intrpt1", "ax"
+ .macro int_hand vecnum, vecname, c_routine, processing=handle_interrupt
+ .org (\vecnum << 8)
+ __int_hand \vecnum, \vecname, \c_routine, \processing
+ .endm
+
+/* Include .intrpt array of interrupt vectors */
+ .section ".intrpt", "ax"
+ .global intrpt_start
+intrpt_start:
#define op_handle_perf_interrupt bad_intr
#define op_handle_aux_perf_interrupt bad_intr
@@ -1272,7 +1517,7 @@ STD_ENTRY(fill_ra_stack)
int_hand INT_SWINT_1, SWINT_1, SYSCALL, handle_syscall
int_hand INT_SWINT_0, SWINT_0, do_trap
int_hand INT_ILL_TRANS, ILL_TRANS, do_trap
- int_hand INT_UNALIGN_DATA, UNALIGN_DATA, int_unalign
+ int_hand_unalign_fast INT_UNALIGN_DATA, UNALIGN_DATA
int_hand INT_DTLB_MISS, DTLB_MISS, do_page_fault
int_hand INT_DTLB_ACCESS, DTLB_ACCESS, do_page_fault
int_hand INT_IDN_FIREWALL, IDN_FIREWALL, do_hardwall_trap
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2024-11-15 00:20:50 +0000