RISC-V Fixes for 6.6-rc6

* A handful of build fixes.
 * A fix to avoid mixing up user/kernel-mode breakpoints, which can
   manifest as a hang when mixing k/uprobes with other breakpoint
   sources.
 * A fix to avoid double-allocting crash kernel memory.
 * A fix for tracefs syscall name mangling, which was causing syscalls
   not to show up in tracefs.
 * A fix to the perf driver to enable the hw events when selected, which
   can trigger a BUG on some userspace access patterns.
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Merge tag 'riscv-for-linus-6.6-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux

Pull RISC-V fixes from Palmer Dabbelt:

 - A handful of build fixes

 - A fix to avoid mixing up user/kernel-mode breakpoints, which can
   manifest as a hang when mixing k/uprobes with other breakpoint
   sources

 - A fix to avoid double-allocting crash kernel memory

 - A fix for tracefs syscall name mangling, which was causing syscalls
   not to show up in tracefs

 - A fix to the perf driver to enable the hw events when selected, which
   can trigger a BUG on some userspace access patterns

* tag 'riscv-for-linus-6.6-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
  drivers: perf: Fix panic in riscv SBI mmap support
  riscv: Fix ftrace syscall handling which are now prefixed with __riscv_
  RISC-V: Fix wrong use of CONFIG_HAVE_SOFTIRQ_ON_OWN_STACK
  riscv: kdump: fix crashkernel reserving problem on RISC-V
  riscv: Remove duplicate objcopy flag
  riscv: signal: fix sigaltstack frame size checking
  riscv: errata: andes: Makefile: Fix randconfig build issue
  riscv: Only consider swbp/ss handlers for correct privileged mode
  riscv: kselftests: Fix mm build by removing testcases subdirectory

arch/riscv/Makefile

@@ -6,7 +6,6 @@
 # for more details.
 #
 
-OBJCOPYFLAGS    := -O binary
 LDFLAGS_vmlinux := -z norelro
 ifeq ($(CONFIG_RELOCATABLE),y)
 	LDFLAGS_vmlinux += -shared -Bsymbolic -z notext --emit-relocs

arch/riscv/errata/andes/Makefile

@@ -1 +1,5 @@
+ifdef CONFIG_RISCV_ALTERNATIVE_EARLY
+CFLAGS_errata.o := -mcmodel=medany
+endif
+
 obj-y += errata.o

arch/riscv/include/asm/ftrace.h

@@ -31,6 +31,27 @@ static inline unsigned long ftrace_call_adjust(unsigned long addr)
 	return addr;
 }
 
+/*
+ * Let's do like x86/arm64 and ignore the compat syscalls.
+ */
+#define ARCH_TRACE_IGNORE_COMPAT_SYSCALLS
+static inline bool arch_trace_is_compat_syscall(struct pt_regs *regs)
+{
+	return is_compat_task();
+}
+
+#define ARCH_HAS_SYSCALL_MATCH_SYM_NAME
+static inline bool arch_syscall_match_sym_name(const char *sym,
+					       const char *name)
+{
+	/*
+	 * Since all syscall functions have __riscv_ prefix, we must skip it.
+	 * However, as we described above, we decided to ignore compat
+	 * syscalls, so we don't care about __riscv_compat_ prefix here.
+	 */
+	return !strcmp(sym + 8, name);
+}
+
 struct dyn_arch_ftrace {
 };
 #endif

arch/riscv/include/asm/kprobes.h

@@ -40,6 +40,15 @@ void arch_remove_kprobe(struct kprobe *p);
 int kprobe_fault_handler(struct pt_regs *regs, unsigned int trapnr);
 bool kprobe_breakpoint_handler(struct pt_regs *regs);
 bool kprobe_single_step_handler(struct pt_regs *regs);
+#else
+static inline bool kprobe_breakpoint_handler(struct pt_regs *regs)
+{
+	return false;
+}
 
+static inline bool kprobe_single_step_handler(struct pt_regs *regs)
+{
+	return false;
+}
 #endif /* CONFIG_KPROBES */
 #endif /* _ASM_RISCV_KPROBES_H */

arch/riscv/include/asm/uprobes.h

@@ -34,7 +34,18 @@ struct arch_uprobe {
 	bool simulate;
 };
 
+#ifdef CONFIG_UPROBES
 bool uprobe_breakpoint_handler(struct pt_regs *regs);
 bool uprobe_single_step_handler(struct pt_regs *regs);
+#else
+static inline bool uprobe_breakpoint_handler(struct pt_regs *regs)
+{
+	return false;
+}
 
+static inline bool uprobe_single_step_handler(struct pt_regs *regs)
+{
+	return false;
+}
+#endif /* CONFIG_UPROBES */
 #endif /* _ASM_RISCV_UPROBES_H */

arch/riscv/kernel/irq.c

@@ -60,7 +60,7 @@ static void init_irq_stacks(void)
 }
 #endif /* CONFIG_VMAP_STACK */
 
-#ifdef CONFIG_HAVE_SOFTIRQ_ON_OWN_STACK
+#ifdef CONFIG_SOFTIRQ_ON_OWN_STACK
 void do_softirq_own_stack(void)
 {
 #ifdef CONFIG_IRQ_STACKS
@@ -92,7 +92,7 @@ void do_softirq_own_stack(void)
 #endif
 		__do_softirq();
 }
-#endif /* CONFIG_HAVE_SOFTIRQ_ON_OWN_STACK */
+#endif /* CONFIG_SOFTIRQ_ON_OWN_STACK */
 
 #else
 static void init_irq_stacks(void) {}

arch/riscv/kernel/setup.c

@@ -173,19 +173,6 @@ static void __init init_resources(void)
 	if (ret < 0)
 		goto error;
 
-#ifdef CONFIG_KEXEC_CORE
-	if (crashk_res.start != crashk_res.end) {
-		ret = add_resource(&iomem_resource, &crashk_res);
-		if (ret < 0)
-			goto error;
-	}
-	if (crashk_low_res.start != crashk_low_res.end) {
-		ret = add_resource(&iomem_resource, &crashk_low_res);
-		if (ret < 0)
-			goto error;
-	}
-#endif
-
 #ifdef CONFIG_CRASH_DUMP
 	if (elfcorehdr_size > 0) {
 		elfcorehdr_res.start = elfcorehdr_addr;

arch/riscv/kernel/signal.c

@@ -311,13 +311,6 @@ static inline void __user *get_sigframe(struct ksignal *ksig,
 	/* Align the stack frame. */
 	sp &= ~0xfUL;
 
-	/*
-	 * Fail if the size of the altstack is not large enough for the
-	 * sigframe construction.
-	 */
-	if (current->sas_ss_size && sp < current->sas_ss_sp)
-		return (void __user __force *)-1UL;
-
 	return (void __user *)sp;
 }
 

arch/riscv/kernel/traps.c

@@ -13,6 +13,8 @@
 #include <linux/kdebug.h>
 #include <linux/uaccess.h>
 #include <linux/kprobes.h>
+#include <linux/uprobes.h>
+#include <asm/uprobes.h>
 #include <linux/mm.h>
 #include <linux/module.h>
 #include <linux/irq.h>
@@ -247,22 +249,28 @@ static inline unsigned long get_break_insn_length(unsigned long pc)
 	return GET_INSN_LENGTH(insn);
 }
 
+static bool probe_single_step_handler(struct pt_regs *regs)
+{
+	bool user = user_mode(regs);
+
+	return user ? uprobe_single_step_handler(regs) : kprobe_single_step_handler(regs);
+}
+
+static bool probe_breakpoint_handler(struct pt_regs *regs)
+{
+	bool user = user_mode(regs);
+
+	return user ? uprobe_breakpoint_handler(regs) : kprobe_breakpoint_handler(regs);
+}
+
 void handle_break(struct pt_regs *regs)
 {
-#ifdef CONFIG_KPROBES
-	if (kprobe_single_step_handler(regs))
+	if (probe_single_step_handler(regs))
 		return;
 
-	if (kprobe_breakpoint_handler(regs))
-		return;
-#endif
-#ifdef CONFIG_UPROBES
-	if (uprobe_single_step_handler(regs))
+	if (probe_breakpoint_handler(regs))
 		return;
 
-	if (uprobe_breakpoint_handler(regs))
-		return;
-#endif
 	current->thread.bad_cause = regs->cause;
 
 	if (user_mode(regs))

drivers/perf/riscv_pmu.c

@@ -23,7 +23,8 @@ static bool riscv_perf_user_access(struct perf_event *event)
 	return ((event->attr.type == PERF_TYPE_HARDWARE) ||
 		(event->attr.type == PERF_TYPE_HW_CACHE) ||
 		(event->attr.type == PERF_TYPE_RAW)) &&
-		!!(event->hw.flags & PERF_EVENT_FLAG_USER_READ_CNT);
+		!!(event->hw.flags & PERF_EVENT_FLAG_USER_READ_CNT) &&
+		(event->hw.idx != -1);
 }
 
 void arch_perf_update_userpage(struct perf_event *event,

drivers/perf/riscv_pmu_sbi.c

@@ -510,16 +510,18 @@ static void pmu_sbi_set_scounteren(void *arg)
 {
 	struct perf_event *event = (struct perf_event *)arg;
 
-	csr_write(CSR_SCOUNTEREN,
-		  csr_read(CSR_SCOUNTEREN) | (1 << pmu_sbi_csr_index(event)));
+	if (event->hw.idx != -1)
+		csr_write(CSR_SCOUNTEREN,
+			  csr_read(CSR_SCOUNTEREN) | (1 << pmu_sbi_csr_index(event)));
 }
 
 static void pmu_sbi_reset_scounteren(void *arg)
 {
 	struct perf_event *event = (struct perf_event *)arg;
 
-	csr_write(CSR_SCOUNTEREN,
-		  csr_read(CSR_SCOUNTEREN) & ~(1 << pmu_sbi_csr_index(event)));
+	if (event->hw.idx != -1)
+		csr_write(CSR_SCOUNTEREN,
+			  csr_read(CSR_SCOUNTEREN) & ~(1 << pmu_sbi_csr_index(event)));
 }
 
 static void pmu_sbi_ctr_start(struct perf_event *event, u64 ival)
@@ -541,7 +543,8 @@ static void pmu_sbi_ctr_start(struct perf_event *event, u64 ival)
 
 	if ((hwc->flags & PERF_EVENT_FLAG_USER_ACCESS) &&
 	    (hwc->flags & PERF_EVENT_FLAG_USER_READ_CNT))
-		pmu_sbi_set_scounteren((void *)event);
+		on_each_cpu_mask(mm_cpumask(event->owner->mm),
+				 pmu_sbi_set_scounteren, (void *)event, 1);
 }
 
 static void pmu_sbi_ctr_stop(struct perf_event *event, unsigned long flag)
@@ -551,7 +554,8 @@ static void pmu_sbi_ctr_stop(struct perf_event *event, unsigned long flag)
 
 	if ((hwc->flags & PERF_EVENT_FLAG_USER_ACCESS) &&
 	    (hwc->flags & PERF_EVENT_FLAG_USER_READ_CNT))
-		pmu_sbi_reset_scounteren((void *)event);
+		on_each_cpu_mask(mm_cpumask(event->owner->mm),
+				 pmu_sbi_reset_scounteren, (void *)event, 1);
 
 	ret = sbi_ecall(SBI_EXT_PMU, SBI_EXT_PMU_COUNTER_STOP, hwc->idx, 1, flag, 0, 0, 0);
 	if (ret.error && (ret.error != SBI_ERR_ALREADY_STOPPED) &&

tools/testing/selftests/riscv/mm/Makefile

@@ -5,11 +5,11 @@
 # Additional include paths needed by kselftest.h and local headers
 CFLAGS += -D_GNU_SOURCE -std=gnu99 -I.
 
-TEST_GEN_FILES := testcases/mmap_default testcases/mmap_bottomup
+TEST_GEN_FILES := mmap_default mmap_bottomup
 
-TEST_PROGS := testcases/run_mmap.sh
+TEST_PROGS := run_mmap.sh
 
 include ../../lib.mk
 
-$(OUTPUT)/mm: testcases/mmap_default.c testcases/mmap_bottomup.c testcases/mmap_tests.h
+$(OUTPUT)/mm: mmap_default.c mmap_bottomup.c mmap_tests.h
 	$(CC) -o$@ $(CFLAGS) $(LDFLAGS) $^

tools/testing/selftests/riscv/mm/mmap_bottomup.c

@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0-only
 #include <sys/mman.h>
-#include <testcases/mmap_test.h>
+#include <mmap_test.h>
 
 #include "../../kselftest_harness.h"
 

tools/testing/selftests/riscv/mm/mmap_default.c

@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0-only
 #include <sys/mman.h>
-#include <testcases/mmap_test.h>
+#include <mmap_test.h>
 
 #include "../../kselftest_harness.h"