evl: add support for compat mode

Compat mode (CONFIG_COMPAT) allows application binaries built for a 32bit architecture to issue system calls to a 64bit kernel which implements such compatibility support. This work builds on the y2038 sanitization which eliminated the remaining assumptions about the size of native long integers in the same move. Although these changes enable armv7 binaries to call an armv8 kernel, most of them are architecture-independent, and follow this pattern: - .compat_ioctl and .compat_oob_ioctl handlers are added to all file operations structs, pointing at compat_ptr_ioctl() compat_ptr_oob_ioctl() respectively. - all pointers passed by applications within ioctl() argument structs are conveyed as generic 64bit values. These changes mandate upgrading the ABI revision to Freescale#20. Signed-off-by: Philippe Gerum <rpm@xenomai.org>
MrCry0 · Jun 22, 2023 · 9e123d4 · 9e123d4
1 parent 34f0bbb
commit 9e123d4
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Showing 25 changed files with 329 additions and 227 deletions.
diff --git a/arch/arm/include/asm/evl/syscall.h b/arch/arm/include/asm/evl/syscall.h
@@ -6,30 +6,34 @@
 #include <asm/unistd.h>
 #include <asm/ptrace.h>
 #include <asm/syscall.h>
-#include <uapi/asm/dovetail.h>
+#include <uapi/asm-generic/dovetail.h>
 
 #define raw_put_user(src, dst)  __put_user(src, dst)
 #define raw_get_user(dst, src)  __get_user(dst, src)
 
-#define is_oob_syscall(__regs)	((__regs)->ARM_r7 == __ARM_NR_dovetail)
-#define oob_syscall_nr(__regs)	((__regs)->ARM_ORIG_r0)
-
 #define oob_retval(__regs)	((__regs)->ARM_r0)
-#define oob_arg1(__regs)	((__regs)->ARM_r1)
-#define oob_arg2(__regs)	((__regs)->ARM_r2)
-#define oob_arg3(__regs)	((__regs)->ARM_r3)
-#define oob_arg4(__regs)	((__regs)->ARM_r4)
-#define oob_arg5(__regs)	((__regs)->ARM_r5)
-
-/*
- * Fetch and test inband syscall number (valid only if
- * !is_oob_syscall(__regs)).
- */
-#define inband_syscall_nr(__regs, __nr)					\
-	({								\
-		*(__nr) = (__regs)->ARM_r7;				\
-		*(__nr) < NR_syscalls || *(__nr) >= __ARM_NR_BASE;	\
-	})
+#define oob_arg1(__regs)	((__regs)->ARM_r0)
+#define oob_arg2(__regs)	((__regs)->ARM_r1)
+#define oob_arg3(__regs)	((__regs)->ARM_r2)
+#define oob_arg4(__regs)	((__regs)->ARM_r3)
+#define oob_arg5(__regs)	((__regs)->ARM_r4)
+
+static inline bool is_oob_syscall(struct pt_regs *regs)
+{
+	return !!(regs->ARM_r7 & __OOB_SYSCALL_BIT);
+}
+
+static inline unsigned int oob_syscall_nr(struct pt_regs *regs)
+{
+	return regs->ARM_r7 & ~__OOB_SYSCALL_BIT;
+}
+
+static inline
+bool inband_syscall_nr(struct pt_regs *regs, unsigned int *nr)
+{
+	*nr = regs->ARM_r7;
+	return *nr < NR_syscalls || *nr >= __ARM_NR_BASE;
+}
 
 static inline void
 set_oob_error(struct pt_regs *regs, int err)
@@ -43,4 +47,9 @@ void set_oob_retval(struct pt_regs *regs, long ret)
 	oob_retval(regs) = ret;
 }
 
+static inline bool is_compat_oob_call(void)
+{
+	return false;
+}
+
 #endif /* !_EVL_ARM_ASM_SYSCALL_H */
diff --git a/arch/arm64/include/asm/evl/syscall.h b/arch/arm64/include/asm/evl/syscall.h
@@ -5,41 +5,58 @@
 #include <linux/uaccess.h>
 #include <asm/unistd.h>
 #include <asm/ptrace.h>
-#include <uapi/asm/evl/syscall.h>
+#include <uapi/asm-generic/dovetail.h>
 
 #define raw_put_user(src, dst)  __put_user(src, dst)
 #define raw_get_user(dst, src)  __get_user(dst, src)
 
-#define is_oob_syscall(__regs)	((__regs)->syscallno & __EVL_SYSCALL_BIT)
-#define oob_syscall_nr(__regs)	((__regs)->syscallno & ~__EVL_SYSCALL_BIT)
-
 #define oob_retval(__regs)	((__regs)->regs[0])
 #define oob_arg1(__regs)	((__regs)->regs[0])
 #define oob_arg2(__regs)	((__regs)->regs[1])
 #define oob_arg3(__regs)	((__regs)->regs[2])
 #define oob_arg4(__regs)	((__regs)->regs[3])
 #define oob_arg5(__regs)	((__regs)->regs[4])
 
-/*
- * Fetch and test inband syscall number (valid only if
- * !is_oob_syscall(__regs)).
- */
-#define inband_syscall_nr(__regs, __nr)			\
-	({						\
-		*(__nr) = oob_syscall_nr(__regs);	\
-		!is_oob_syscall(__regs);		\
-	})
-
-static inline void
-set_oob_error(struct pt_regs *regs, int err)
+#define __ARM_NR_BASE_compat		0xf0000
+
+static inline bool is_oob_syscall(const struct pt_regs *regs)
+{
+	return !!(regs->syscallno & __OOB_SYSCALL_BIT);
+}
+
+static inline unsigned int oob_syscall_nr(const struct pt_regs *regs)
+{
+	return regs->syscallno & ~__OOB_SYSCALL_BIT;
+}
+
+static inline bool
+inband_syscall_nr(struct pt_regs *regs, unsigned int *nr)
+{
+	*nr = oob_syscall_nr(regs);
+
+	return !is_oob_syscall(regs);
+}
+
+static inline void set_oob_error(struct pt_regs *regs, int err)
 {
 	oob_retval(regs) = err;
 }
 
-static inline
-void set_oob_retval(struct pt_regs *regs, long ret)
+static inline void set_oob_retval(struct pt_regs *regs, long ret)
 {
 	oob_retval(regs) = ret;
 }
 
+#ifdef CONFIG_COMPAT
+static inline bool is_compat_oob_call(void)
+{
+	return is_compat_task();
+}
+#else
+static inline bool is_compat_oob_call(void)
+{
+	return false;
+}
+#endif
+
 #endif /* !_EVL_ARM64_ASM_SYSCALL_H */
diff --git a/arch/arm64/include/uapi/asm/evl/syscall.h b/arch/arm64/include/uapi/asm/evl/syscall.h
diff --git a/arch/x86/include/asm/evl/syscall.h b/arch/x86/include/asm/evl/syscall.h
@@ -5,41 +5,48 @@
 #include <linux/uaccess.h>
 #include <asm/unistd.h>
 #include <asm/ptrace.h>
-#include <uapi/asm/evl/syscall.h>
+#include <uapi/asm-generic/dovetail.h>
 
 #define raw_put_user(src, dst)  __put_user(src, dst)
 #define raw_get_user(dst, src)  __get_user(dst, src)
 
-#define is_oob_syscall(__regs)	((__regs)->orig_ax & __EVL_SYSCALL_BIT)
-#define oob_syscall_nr(__regs)	((__regs)->orig_ax & ~__EVL_SYSCALL_BIT)
-
 #define oob_retval(__regs)	((__regs)->ax)
 #define oob_arg1(__regs)	((__regs)->di)
 #define oob_arg2(__regs)	((__regs)->si)
 #define oob_arg3(__regs)	((__regs)->dx)
 #define oob_arg4(__regs)	((__regs)->r10)
 #define oob_arg5(__regs)	((__regs)->r8)
 
-/*
- * Fetch and test inband syscall number (valid only if
- * !is_oob_syscall(__regs)).
- */
-#define inband_syscall_nr(__regs, __nr)			\
-	({						\
-		*(__nr) = oob_syscall_nr(__regs);	\
-		!is_oob_syscall(__regs);		\
-	})
-
-static inline void
-set_oob_error(struct pt_regs *regs, int err)
+static inline bool is_oob_syscall(const struct pt_regs *regs)
 {
-	oob_retval(regs) = err;
+	return !!(regs->orig_ax & __OOB_SYSCALL_BIT);
+}
+
+static inline unsigned int oob_syscall_nr(const struct pt_regs *regs)
+{
+	return regs->orig_ax & ~__OOB_SYSCALL_BIT;
 }
 
 static inline
-void set_oob_retval(struct pt_regs *regs, long ret)
+bool inband_syscall_nr(struct pt_regs *regs, unsigned int *nr)
+{
+	*nr = oob_syscall_nr(regs);
+	return !is_oob_syscall(regs);
+}
+
+static inline void set_oob_error(struct pt_regs *regs, int err)
+{
+	oob_retval(regs) = err;
+}
+
+static inline void set_oob_retval(struct pt_regs *regs, long ret)
 {
 	oob_retval(regs) = ret;
 }
 
+static inline bool is_compat_oob_call(void)
+{
+	return in_ia32_syscall();
+}
+
 #endif /* !_EVL_X86_ASM_SYSCALL_H */
diff --git a/arch/x86/include/uapi/asm/evl/syscall.h b/arch/x86/include/uapi/asm/evl/syscall.h
diff --git a/drivers/evl/hectic.c b/drivers/evl/hectic.c
@@ -661,6 +661,10 @@ static const struct file_operations hectic_fops = {
 	.release	= hectic_release,
 	.unlocked_ioctl	= hectic_ioctl,
 	.oob_ioctl	= hectic_oob_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl	= compat_ptr_ioctl,
+	.compat_oob_ioctl  = compat_ptr_oob_ioctl,
+#endif
 };
 
 static dev_t hectic_devt;

diff --git a/drivers/evl/latmus.c b/drivers/evl/latmus.c
@@ -14,12 +14,12 @@
 #include <linux/cdev.h>
 #include <linux/fs.h>
 #include <linux/fcntl.h>
-#include <linux/uaccess.h>
 #include <evl/file.h>
 #include <evl/flag.h>
 #include <evl/clock.h>
 #include <evl/thread.h>
 #include <evl/xbuf.h>
+#include <evl/uaccess.h>
 #include <uapi/evl/devices/latmus.h>
 #include <trace/events/evl.h>
 
@@ -779,7 +779,7 @@ static int run_tuning(struct latmus_runner *runner,
 
 	gravity = runner->get_gravity(runner);
 
-	if (raw_copy_to_user(result->data, &gravity, sizeof(gravity)))
+	if (raw_copy_to_user_ptr64(result->data_ptr, &gravity, sizeof(gravity)))
 		return -EFAULT;
 
 	return 0;
@@ -817,7 +817,7 @@ static int run_measurement(struct latmus_runner *runner,
 	if (result->len != sizeof(mr))
 		return -EINVAL;
 
-	if (raw_copy_from_user(&mr, result->data, sizeof(mr)))
+	if (raw_copy_from_user_ptr64(&mr, result->data_ptr, sizeof(mr)))
 		return -EFAULT;
 
 	ret = measure_continously(runner);
@@ -833,15 +833,16 @@ static int run_measurement(struct latmus_runner *runner,
 	last.sum_lat = state->sum;
 	last.overruns = state->overruns;
 	last.samples = state->cur_samples;
-	if (raw_copy_to_user(mr.last, &last, sizeof(last)))
+	if (raw_copy_to_user_ptr64(mr.last_ptr, &last, sizeof(last)))
 		return -EFAULT;
 
 	if (runner->histogram) {
 		len = runner->hcells * sizeof(s32);
 		if (len > mr.len)
 			len = result->len;
 		if (len > 0 &&
-		    raw_copy_to_user(mr.histogram, runner->histogram, len))
+		    raw_copy_to_user_ptr64(mr.histogram_ptr,
+					   runner->histogram, len))
 			return -EFAULT;
 	}
 
@@ -1020,6 +1021,10 @@ static const struct file_operations latmus_fops = {
 	.release	= latmus_release,
 	.unlocked_ioctl	= latmus_ioctl,
 	.oob_ioctl	= latmus_oob_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl	= compat_ptr_ioctl,
+	.compat_oob_ioctl  = compat_ptr_oob_ioctl,
+#endif
 };
 
 static dev_t latmus_devt;

diff --git a/include/evl/uaccess.h b/include/evl/uaccess.h
@@ -0,0 +1,27 @@
+/*
+ * SPDX-License-Identifier: GPL-2.0
+ *
+ * Copyright (C) 2020 Philippe Gerum  <rpm@xenomai.org>
+ */
+
+#ifndef _EVL_UACCESS_H
+#define _EVL_UACCESS_H
+
+#include <linux/uaccess.h>
+
+static inline unsigned long __must_check
+raw_copy_from_user_ptr64(void *to, u64 from_ptr, unsigned long n)
+{
+	return raw_copy_from_user(to, (void *)(long)from_ptr, n);
+}
+
+static inline unsigned long __must_check
+raw_copy_to_user_ptr64(u64 to, const void *from, unsigned long n)
+{
+	return raw_copy_to_user((void *)(long)to, from, n);
+}
+
+#define evl_ptrval64(__ptr)		((u64)(long)(__ptr))
+#define evl_valptr64(__ptrval, __type)	((__type *)(long)(__ptrval))
+
+#endif /* !_EVL_UACCESS_H */
diff --git a/include/uapi/evl/clock.h b/include/uapi/evl/clock.h
@@ -25,8 +25,8 @@
 #define EVL_CLKIOC_NEW_TIMER	_IO(EVL_CLOCK_IOCBASE, 5)
 
 struct evl_timerfd_setreq {
-	struct __evl_itimerspec *value;
-	struct __evl_itimerspec *ovalue;
+	__u64 value_ptr;       /* (struct __evl_itimerspec *value) */
+	__u64 ovalue_ptr;      /* (struct __evl_itimerspec *ovalue) */
 };
 
 #define EVL_TIMERFD_IOCBASE	't'

diff --git a/include/uapi/evl/control.h b/include/uapi/evl/control.h
@@ -11,14 +11,14 @@
 #include <uapi/evl/sched.h>
 
 /* Earliest ABI level we support. */
-#define EVL_ABI_BASE   19
+#define EVL_ABI_BASE   20
 /*
  * Current/latest ABI level we support. We may decouple the base and
  * current ABI levels by providing backward compatibility from the
  * latter to the former. CAUTION: a litteral value is required for the
  * current ABI definition (scripts reading this may be naive).
  */
-#define EVL_ABI_LEVEL  19
+#define EVL_ABI_LEVEL  20
 
 #define EVL_CONTROL_DEV  "/dev/evl/control"
 
@@ -31,7 +31,7 @@ struct evl_core_info {
 
 struct evl_cpu_state {
 	__u32 cpu;
-	__u32 *state;
+	__u64 state_ptr;	/* (__u32 *state) */
 };
 
 #define EVL_CONTROL_IOCBASE	'C'

diff --git a/include/uapi/evl/devices/latmus.h b/include/uapi/evl/devices/latmus.h
@@ -44,13 +44,13 @@ struct latmus_measurement {
 };
 
 struct latmus_measurement_result {
-	struct latmus_measurement *last;
-	__s32 *histogram;
+	__u64 last_ptr;		/* (struct latmus_measurement *last) */
+	__u64 histogram_ptr;	/* (__s32 *histogram) */
 	__u32 len;
 };
 
 struct latmus_result {
-	void *data;
+	__u64 data_ptr;		/* (void *data) */
 	__u32 len;
 };
 

diff --git a/include/uapi/evl/factory.h b/include/uapi/evl/factory.h
@@ -18,8 +18,8 @@ struct evl_element_ids {
 };
 
 struct evl_clone_req {
-	const char *name;
-	void *attrs;
+	__u64 name_ptr;		/* (const char *name) */
+	__u64 attrs_ptr;	/* (void *attrs) */
 	struct evl_element_ids eids;
 };
 

diff --git a/include/uapi/evl/monitor.h b/include/uapi/evl/monitor.h
@@ -53,7 +53,7 @@ struct evl_monitor_state {
 };
 
 struct evl_monitor_waitreq {
-	struct __evl_timespec *timeout;
+	__u64 timeout_ptr;	/* (struct __evl_timespec *timeout) */
 	__s32 gatefd;
 	__s32 status;
 	__s32 value;