linux_dsm_epyc7002/drivers/gpu/drm/i915/i915_utils.h
Chris Wilson 9d1305ef80 drm/i915: Introduce the i915_user_extension_method
An idea for extending uABI inspired by Vulkan's extension chains.
Instead of expanding the data struct for each ioctl every time we need
to add a new feature, define an extension chain instead. As we add
optional interfaces to control the ioctl, we define a new extension
struct that can be linked into the ioctl data only when required by the
user. The key advantage being able to ignore large control structs for
optional interfaces/extensions, while being able to process them in a
consistent manner.

In comparison to other extensible ioctls, the key difference is the
use of a linked chain of extension structs vs an array of tagged
pointers. For example,

struct drm_amdgpu_cs_chunk {
        __u32           chunk_id;
        __u32           length_dw;
        __u64           chunk_data;
};

struct drm_amdgpu_cs_in {
        __u32           ctx_id;
        __u32           bo_list_handle;
        __u32           num_chunks;
        __u32           _pad;
        __u64           chunks;
};

allows userspace to pass in array of pointers to extension structs, but
must therefore keep constructing that array along side the command stream.
In dynamic situations like that, a linked list is preferred and does not
similar from extra cache line misses as the extension structs themselves
must still be loaded separate to the chunks array.

v2: Apply the tail call optimisation directly to nip the worry of stack
overflow in the bud.
v3: Defend against recursion.
v4: Fixup local types to match new uabi

Opens:
- do we include the result as an out-field in each chain?
struct i915_user_extension {
	__u64 next_extension;
	__u64 name;
	__s32 result;
	__u32 mbz; /* reserved for future use */
};
* Undecided, so provision some room for future expansion.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190322092325.5883-1-chris@chris-wilson.co.uk
2019-03-22 13:12:30 +00:00

199 lines
5.7 KiB
C

/*
* Copyright © 2016 Intel Corporation
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*
*/
#ifndef __I915_UTILS_H
#define __I915_UTILS_H
#undef WARN_ON
/* Many gcc seem to no see through this and fall over :( */
#if 0
#define WARN_ON(x) ({ \
bool __i915_warn_cond = (x); \
if (__builtin_constant_p(__i915_warn_cond)) \
BUILD_BUG_ON(__i915_warn_cond); \
WARN(__i915_warn_cond, "WARN_ON(" #x ")"); })
#else
#define WARN_ON(x) WARN((x), "%s", "WARN_ON(" __stringify(x) ")")
#endif
#undef WARN_ON_ONCE
#define WARN_ON_ONCE(x) WARN_ONCE((x), "%s", "WARN_ON_ONCE(" __stringify(x) ")")
#define MISSING_CASE(x) WARN(1, "Missing case (%s == %ld)\n", \
__stringify(x), (long)(x))
#if defined(GCC_VERSION) && GCC_VERSION >= 70000
#define add_overflows_t(T, A, B) \
__builtin_add_overflow_p((A), (B), (T)0)
#else
#define add_overflows_t(T, A, B) ({ \
typeof(A) a = (A); \
typeof(B) b = (B); \
(T)(a + b) < a; \
})
#endif
#define add_overflows(A, B) \
add_overflows_t(typeof((A) + (B)), (A), (B))
#define range_overflows(start, size, max) ({ \
typeof(start) start__ = (start); \
typeof(size) size__ = (size); \
typeof(max) max__ = (max); \
(void)(&start__ == &size__); \
(void)(&start__ == &max__); \
start__ > max__ || size__ > max__ - start__; \
})
#define range_overflows_t(type, start, size, max) \
range_overflows((type)(start), (type)(size), (type)(max))
/* Note we don't consider signbits :| */
#define overflows_type(x, T) \
(sizeof(x) > sizeof(T) && (x) >> BITS_PER_TYPE(T))
#define ptr_mask_bits(ptr, n) ({ \
unsigned long __v = (unsigned long)(ptr); \
(typeof(ptr))(__v & -BIT(n)); \
})
#define ptr_unmask_bits(ptr, n) ((unsigned long)(ptr) & (BIT(n) - 1))
#define ptr_unpack_bits(ptr, bits, n) ({ \
unsigned long __v = (unsigned long)(ptr); \
*(bits) = __v & (BIT(n) - 1); \
(typeof(ptr))(__v & -BIT(n)); \
})
#define ptr_pack_bits(ptr, bits, n) ({ \
unsigned long __bits = (bits); \
GEM_BUG_ON(__bits & -BIT(n)); \
((typeof(ptr))((unsigned long)(ptr) | __bits)); \
})
#define page_mask_bits(ptr) ptr_mask_bits(ptr, PAGE_SHIFT)
#define page_unmask_bits(ptr) ptr_unmask_bits(ptr, PAGE_SHIFT)
#define page_pack_bits(ptr, bits) ptr_pack_bits(ptr, bits, PAGE_SHIFT)
#define page_unpack_bits(ptr, bits) ptr_unpack_bits(ptr, bits, PAGE_SHIFT)
#define ptr_offset(ptr, member) offsetof(typeof(*(ptr)), member)
#define fetch_and_zero(ptr) ({ \
typeof(*ptr) __T = *(ptr); \
*(ptr) = (typeof(*ptr))0; \
__T; \
})
/*
* container_of_user: Extract the superclass from a pointer to a member.
*
* Exactly like container_of() with the exception that it plays nicely
* with sparse for __user @ptr.
*/
#define container_of_user(ptr, type, member) ({ \
void __user *__mptr = (void __user *)(ptr); \
BUILD_BUG_ON_MSG(!__same_type(*(ptr), ((type *)0)->member) && \
!__same_type(*(ptr), void), \
"pointer type mismatch in container_of()"); \
((type __user *)(__mptr - offsetof(type, member))); })
/*
* check_user_mbz: Check that a user value exists and is zero
*
* Frequently in our uABI we reserve space for future extensions, and
* two ensure that userspace is prepared we enforce that space must
* be zero. (Then any future extension can safely assume a default value
* of 0.)
*
* check_user_mbz() combines checking that the user pointer is accessible
* and that the contained value is zero.
*
* Returns: -EFAULT if not accessible, -EINVAL if !zero, or 0 on success.
*/
#define check_user_mbz(U) ({ \
typeof(*(U)) mbz__; \
get_user(mbz__, (U)) ? -EFAULT : mbz__ ? -EINVAL : 0; \
})
static inline u64 ptr_to_u64(const void *ptr)
{
return (uintptr_t)ptr;
}
#define u64_to_ptr(T, x) ({ \
typecheck(u64, x); \
(T *)(uintptr_t)(x); \
})
#define __mask_next_bit(mask) ({ \
int __idx = ffs(mask) - 1; \
mask &= ~BIT(__idx); \
__idx; \
})
#include <linux/list.h>
static inline int list_is_first(const struct list_head *list,
const struct list_head *head)
{
return head->next == list;
}
static inline void __list_del_many(struct list_head *head,
struct list_head *first)
{
first->prev = head;
WRITE_ONCE(head->next, first);
}
/*
* Wait until the work is finally complete, even if it tries to postpone
* by requeueing itself. Note, that if the worker never cancels itself,
* we will spin forever.
*/
static inline void drain_delayed_work(struct delayed_work *dw)
{
do {
while (flush_delayed_work(dw))
;
} while (delayed_work_pending(dw));
}
static inline const char *yesno(bool v)
{
return v ? "yes" : "no";
}
static inline const char *onoff(bool v)
{
return v ? "on" : "off";
}
static inline const char *enableddisabled(bool v)
{
return v ? "enabled" : "disabled";
}
#endif /* !__I915_UTILS_H */