diff options
Diffstat (limited to 'arch/tile/kernel/intvec_64.S')
| -rw-r--r-- | arch/tile/kernel/intvec_64.S | 231 |
1 files changed, 224 insertions, 7 deletions
diff --git a/arch/tile/kernel/intvec_64.S b/arch/tile/kernel/intvec_64.S index 85d483957027..884af9ea5bed 100644 --- a/arch/tile/kernel/intvec_64.S +++ b/arch/tile/kernel/intvec_64.S @@ -17,11 +17,13 @@ #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> @@ -98,6 +100,189 @@ } .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. */ + mm r3, zero, LOG2_THREAD_SIZE, 63 +#if THREAD_SIZE < 65536 + addli r3, r3, -(PAGE_SIZE - THREAD_INFO_UNALIGN_JIT_TMP_OFFSET) +#else + addli r3, r3, -(PAGE_SIZE/2) + addli r3, r3, -(PAGE_SIZE/2 - THREAD_INFO_UNALIGN_JIT_TMP_OFFSET) +#endif + + /* + * 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 +303,21 @@ 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 + andi r0, r0, SPR_EX_CONTEXT_1_1__PL_MASK /* mask off ICS */ + } .ifc \vecnum, INT_DOUBLE_FAULT /* @@ -176,7 +367,7 @@ 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 @@ -1223,10 +1414,31 @@ 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) @@ -1240,6 +1452,11 @@ STD_ENTRY(fill_ra_stack) 4: jrp r0 STD_ENDPROC(fill_ra_stack) + .macro int_hand vecnum, vecname, c_routine, processing=handle_interrupt + .org (\vecnum << 8) + __int_hand \vecnum, \vecname, \c_routine, \processing + .endm + /* Include .intrpt1 array of interrupt vectors */ .section ".intrpt1", "ax" @@ -1272,7 +1489,7 @@ 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 |