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[121.44.69.75]) by smtp.gmail.com with ESMTPSA id u4-20020a170902b28400b001a19d4592e1sm1430990plr.282.2023.03.17.05.36.42 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 17 Mar 2023 05:36:44 -0700 (PDT) From: Nicholas Piggin To: kvm@vger.kernel.org Cc: Nicholas Piggin , linuxppc-dev@lists.ozlabs.org, Laurent Vivier , Thomas Huth Subject: [kvm-unit-tests PATCH 3/7] powerpc: abstract H_CEDE calls into a sleep() function Date: Fri, 17 Mar 2023 22:36:10 +1000 Message-Id: <20230317123614.3687163-3-npiggin@gmail.com> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20230317123614.3687163-1-npiggin@gmail.com> References: <20230317123614.3687163-1-npiggin@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org This consolidates several implementations, and it no longer leaves MSR[EE] enabled after the decrementer interrupt is handled, but rather disables it on return. The handler no longer allows a continuous ticking, but rather dec has to be re-armed and EE re-enabled (e.g., via H_CEDE hcall) each time. Signed-off-by: Nicholas Piggin --- lib/powerpc/asm/handlers.h | 2 +- lib/powerpc/asm/ppc_asm.h | 1 + lib/powerpc/asm/processor.h | 1 + lib/powerpc/handlers.c | 10 ++++------ lib/powerpc/processor.c | 31 +++++++++++++++++++++++++++++++ powerpc/sprs.c | 6 +----- powerpc/tm.c | 20 +------------------- 7 files changed, 40 insertions(+), 31 deletions(-) diff --git a/lib/powerpc/asm/handlers.h b/lib/powerpc/asm/handlers.h index 64ba727..e4a0cd4 100644 --- a/lib/powerpc/asm/handlers.h +++ b/lib/powerpc/asm/handlers.h @@ -3,6 +3,6 @@ #include -void dec_except_handler(struct pt_regs *regs, void *data); +void dec_handler_oneshot(struct pt_regs *regs, void *data); #endif /* _ASMPOWERPC_HANDLERS_H_ */ diff --git a/lib/powerpc/asm/ppc_asm.h b/lib/powerpc/asm/ppc_asm.h index 1b85f6b..6299ff5 100644 --- a/lib/powerpc/asm/ppc_asm.h +++ b/lib/powerpc/asm/ppc_asm.h @@ -36,6 +36,7 @@ #endif /* __BYTE_ORDER__ */ /* Machine State Register definitions: */ +#define MSR_EE_BIT 15 /* External Interrupts Enable */ #define MSR_SF_BIT 63 /* 64-bit mode */ #endif /* _ASMPOWERPC_PPC_ASM_H */ diff --git a/lib/powerpc/asm/processor.h b/lib/powerpc/asm/processor.h index ac001e1..1467f2c 100644 --- a/lib/powerpc/asm/processor.h +++ b/lib/powerpc/asm/processor.h @@ -20,6 +20,7 @@ static inline uint64_t get_tb(void) extern void delay(uint64_t cycles); extern void udelay(uint64_t us); +extern void sleep(uint64_t cycles); static inline void mdelay(uint64_t ms) { diff --git a/lib/powerpc/handlers.c b/lib/powerpc/handlers.c index c8721e0..296f14f 100644 --- a/lib/powerpc/handlers.c +++ b/lib/powerpc/handlers.c @@ -9,15 +9,13 @@ #include #include #include +#include /* * Generic handler for decrementer exceptions (0x900) - * Just reset the decrementer back to the value specified when registering the - * handler + * Return with MSR[EE] disabled. */ -void dec_except_handler(struct pt_regs *regs __unused, void *data) +void dec_handler_oneshot(struct pt_regs *regs, void *data) { - uint64_t dec = *((uint64_t *) data); - - asm volatile ("mtdec %0" : : "r" (dec)); + regs->msr &= ~(1UL << MSR_EE_BIT); } diff --git a/lib/powerpc/processor.c b/lib/powerpc/processor.c index ec85b9d..f1fb50f 100644 --- a/lib/powerpc/processor.c +++ b/lib/powerpc/processor.c @@ -10,6 +10,8 @@ #include #include #include +#include +#include static struct { void (*func)(struct pt_regs *, void *data); @@ -54,3 +56,32 @@ void udelay(uint64_t us) { delay((us * tb_hz) / 1000000); } + +void sleep(uint64_t cycles) +{ + uint64_t start, end, now; + + start = now = get_tb(); + end = start + cycles; + + while (end > now) { + uint64_t left = end - now; + + /* Could support large decrementer */ + if (left > 0x7fffffff) + left = 0x7fffffff; + + asm volatile ("mtdec %0" : : "r" (left)); + handle_exception(0x900, &dec_handler_oneshot, NULL); + if (hcall(H_CEDE) != H_SUCCESS) { + printf("H_CEDE failed\n"); + abort(); + } + handle_exception(0x900, NULL, NULL); + + if (left < 0x7fffffff) + break; + + now = get_tb(); + } +} diff --git a/powerpc/sprs.c b/powerpc/sprs.c index 5cc1cd1..161a6ba 100644 --- a/powerpc/sprs.c +++ b/powerpc/sprs.c @@ -254,7 +254,6 @@ int main(int argc, char **argv) 0x1234567890ABCDEFULL, 0xFEDCBA0987654321ULL, -1ULL, }; - static uint64_t decr = 0x7FFFFFFF; /* Max value */ for (i = 1; i < argc; i++) { if (!strcmp(argv[i], "-w")) { @@ -288,10 +287,7 @@ int main(int argc, char **argv) if (pause) { migrate_once(); } else { - puts("Sleeping...\n"); - handle_exception(0x900, &dec_except_handler, &decr); - asm volatile ("mtdec %0" : : "r" (0x3FFFFFFF)); - hcall(H_CEDE); + sleep(0x10000000); } get_sprs(after); diff --git a/powerpc/tm.c b/powerpc/tm.c index 65cacdf..61bacf4 100644 --- a/powerpc/tm.c +++ b/powerpc/tm.c @@ -48,17 +48,6 @@ static int count_cpus_with_tm(void) return available; } -static int h_cede(void) -{ - register uint64_t r3 asm("r3") = H_CEDE; - - asm volatile ("sc 1" : "+r"(r3) : - : "r0", "r4", "r5", "r6", "r7", "r8", "r9", - "r10", "r11", "r12", "xer", "ctr", "cc"); - - return r3; -} - /* * Enable transactional memory * Returns: FALSE - Failure @@ -95,14 +84,10 @@ static bool enable_tm(void) static void test_h_cede_tm(int argc, char **argv) { int i; - static uint64_t decr = 0x3FFFFF; /* ~10ms */ if (argc > 2) report_abort("Unsupported argument: '%s'", argv[2]); - handle_exception(0x900, &dec_except_handler, &decr); - asm volatile ("mtdec %0" : : "r" (decr)); - if (!start_all_cpus(halt, 0)) report_abort("Failed to start secondary cpus"); @@ -120,10 +105,7 @@ static void test_h_cede_tm(int argc, char **argv) "bf 2,1b" : : : "cr0"); for (i = 0; i < 500; i++) { - uint64_t rval = h_cede(); - - if (rval != H_SUCCESS) - break; + sleep(0x3FFFFF); /* ~10ms */ mdelay(5); }