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Commit 629a5d87 authored by Juergen Gross's avatar Juergen Gross
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xen: sync include/xen/interface/io/ring.h with Xen's newest version 

Sync include/xen/interface/io/ring.h with Xen's newest version in
order to get the RING_COPY_RESPONSE() and RING_RESPONSE_PROD_OVERFLOW()
macros.

Note that this will correct the wrong license info by adding the
missing original copyright notice.
Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
parent 20600617
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Showing with 156 additions and 122 deletions
include/xen/interface/io/ring.h
View file @ 629a5d87
/* SPDX-License-Identifier: GPL-2.0 */
/****************************************************************************** /******************************************************************************
* ring.h * ring.h
* *
* Shared producer-consumer ring macros. * Shared producer-consumer ring macros.
* *
* 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 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.
*
* Tim Deegan and Andrew Warfield November 2004. * Tim Deegan and Andrew Warfield November 2004.
*/ */
#ifndef __XEN_PUBLIC_IO_RING_H__ #ifndef __XEN_PUBLIC_IO_RING_H__
#define __XEN_PUBLIC_IO_RING_H__ #define __XEN_PUBLIC_IO_RING_H__
/*
* When #include'ing this header, you need to provide the following
* declaration upfront:
* - standard integers types (uint8_t, uint16_t, etc)
* They are provided by stdint.h of the standard headers.
*
* In addition, if you intend to use the FLEX macros, you also need to
* provide the following, before invoking the FLEX macros:
* - size_t
* - memcpy
* - grant_ref_t
* These declarations are provided by string.h of the standard headers,
* and grant_table.h from the Xen public headers.
*/
#include <xen/interface/grant_table.h> #include <xen/interface/grant_table.h>
typedef unsigned int RING_IDX; typedef unsigned int RING_IDX;
/* Round a 32-bit unsigned constant down to the nearest power of two. */ /* Round a 32-bit unsigned constant down to the nearest power of two. */
#define __RD2(_x) (((_x) & 0x00000002) ? 0x2 : ((_x) & 0x1)) #define __RD2(_x) (((_x) & 0x00000002) ? 0x2 : ((_x) & 0x1))
#define __RD4(_x) (((_x) & 0x0000000c) ? __RD2((_x)>>2)<<2 : __RD2(_x)) #define __RD4(_x) (((_x) & 0x0000000c) ? __RD2((_x)>>2)<<2 : __RD2(_x))
#define __RD8(_x) (((_x) & 0x000000f0) ? __RD4((_x)>>4)<<4 : __RD4(_x)) #define __RD8(_x) (((_x) & 0x000000f0) ? __RD4((_x)>>4)<<4 : __RD4(_x))
#define __RD16(_x) (((_x) & 0x0000ff00) ? __RD8((_x)>>8)<<8 : __RD8(_x)) #define __RD16(_x) (((_x) & 0x0000ff00) ? __RD8((_x)>>8)<<8 : __RD8(_x))
...@@ -27,82 +59,79 @@ typedef unsigned int RING_IDX; ...@@ -27,82 +59,79 @@ typedef unsigned int RING_IDX;
* A ring contains as many entries as will fit, rounded down to the nearest * A ring contains as many entries as will fit, rounded down to the nearest
* power of two (so we can mask with (size-1) to loop around). * power of two (so we can mask with (size-1) to loop around).
*/ */
#define __CONST_RING_SIZE(_s, _sz) \ #define __CONST_RING_SIZE(_s, _sz) \
(__RD32(((_sz) - offsetof(struct _s##_sring, ring)) / \ (__RD32(((_sz) - offsetof(struct _s##_sring, ring)) / \
sizeof(((struct _s##_sring *)0)->ring[0]))) sizeof(((struct _s##_sring *)0)->ring[0])))
/* /*
* The same for passing in an actual pointer instead of a name tag. * The same for passing in an actual pointer instead of a name tag.
*/ */
#define __RING_SIZE(_s, _sz) \ #define __RING_SIZE(_s, _sz) \
(__RD32(((_sz) - (long)&(_s)->ring + (long)(_s)) / sizeof((_s)->ring[0]))) (__RD32(((_sz) - (long)(_s)->ring + (long)(_s)) / sizeof((_s)->ring[0])))
/* /*
* Macros to make the correct C datatypes for a new kind of ring. * Macros to make the correct C datatypes for a new kind of ring.
* *
* To make a new ring datatype, you need to have two message structures, * To make a new ring datatype, you need to have two message structures,
* let's say struct request, and struct response already defined. * let's say request_t, and response_t already defined.
* *
* In a header where you want the ring datatype declared, you then do: * In a header where you want the ring datatype declared, you then do:
* *
* DEFINE_RING_TYPES(mytag, struct request, struct response); * DEFINE_RING_TYPES(mytag, request_t, response_t);
* *
* These expand out to give you a set of types, as you can see below. * These expand out to give you a set of types, as you can see below.
* The most important of these are: * The most important of these are:
* *
* struct mytag_sring - The shared ring. * mytag_sring_t - The shared ring.
* struct mytag_front_ring - The 'front' half of the ring. * mytag_front_ring_t - The 'front' half of the ring.
* struct mytag_back_ring - The 'back' half of the ring. * mytag_back_ring_t - The 'back' half of the ring.
* *
* To initialize a ring in your code you need to know the location and size * To initialize a ring in your code you need to know the location and size
* of the shared memory area (PAGE_SIZE, for instance). To initialise * of the shared memory area (PAGE_SIZE, for instance). To initialise
* the front half: * the front half:
* *
* struct mytag_front_ring front_ring; * mytag_front_ring_t front_ring;
* SHARED_RING_INIT((struct mytag_sring *)shared_page); * SHARED_RING_INIT((mytag_sring_t *)shared_page);
* FRONT_RING_INIT(&front_ring, (struct mytag_sring *)shared_page, * FRONT_RING_INIT(&front_ring, (mytag_sring_t *)shared_page, PAGE_SIZE);
* PAGE_SIZE);
* *
* Initializing the back follows similarly (note that only the front * Initializing the back follows similarly (note that only the front
* initializes the shared ring): * initializes the shared ring):
* *
* struct mytag_back_ring back_ring; * mytag_back_ring_t back_ring;
* BACK_RING_INIT(&back_ring, (struct mytag_sring *)shared_page, * BACK_RING_INIT(&back_ring, (mytag_sring_t *)shared_page, PAGE_SIZE);
* PAGE_SIZE);
*/ */
#define DEFINE_RING_TYPES(__name, __req_t, __rsp_t) \ #define DEFINE_RING_TYPES(__name, __req_t, __rsp_t) \
\ \
/* Shared ring entry */ \ /* Shared ring entry */ \
union __name##_sring_entry { \ union __name##_sring_entry { \
__req_t req; \ __req_t req; \
__rsp_t rsp; \ __rsp_t rsp; \
}; \ }; \
\ \
/* Shared ring page */ \ /* Shared ring page */ \
struct __name##_sring { \ struct __name##_sring { \
RING_IDX req_prod, req_event; \ RING_IDX req_prod, req_event; \
RING_IDX rsp_prod, rsp_event; \ RING_IDX rsp_prod, rsp_event; \
uint8_t pad[48]; \ uint8_t __pad[48]; \
union __name##_sring_entry ring[1]; /* variable-length */ \ union __name##_sring_entry ring[1]; /* variable-length */ \
}; \ }; \
\ \
/* "Front" end's private variables */ \ /* "Front" end's private variables */ \
struct __name##_front_ring { \ struct __name##_front_ring { \
RING_IDX req_prod_pvt; \ RING_IDX req_prod_pvt; \
RING_IDX rsp_cons; \ RING_IDX rsp_cons; \
unsigned int nr_ents; \ unsigned int nr_ents; \
struct __name##_sring *sring; \ struct __name##_sring *sring; \
}; \ }; \
\ \
/* "Back" end's private variables */ \ /* "Back" end's private variables */ \
struct __name##_back_ring { \ struct __name##_back_ring { \
RING_IDX rsp_prod_pvt; \ RING_IDX rsp_prod_pvt; \
RING_IDX req_cons; \ RING_IDX req_cons; \
unsigned int nr_ents; \ unsigned int nr_ents; \
struct __name##_sring *sring; \ struct __name##_sring *sring; \
}; }; \
\
/* /*
* Macros for manipulating rings. * Macros for manipulating rings.
* *
...@@ -119,94 +148,99 @@ struct __name##_back_ring { \ ...@@ -119,94 +148,99 @@ struct __name##_back_ring { \
*/ */
/* Initialising empty rings */ /* Initialising empty rings */
#define SHARED_RING_INIT(_s) do { \ #define SHARED_RING_INIT(_s) do { \
(_s)->req_prod = (_s)->rsp_prod = 0; \ (_s)->req_prod = (_s)->rsp_prod = 0; \
(_s)->req_event = (_s)->rsp_event = 1; \ (_s)->req_event = (_s)->rsp_event = 1; \
memset((_s)->pad, 0, sizeof((_s)->pad)); \ (void)memset((_s)->__pad, 0, sizeof((_s)->__pad)); \
} while(0) } while(0)
#define FRONT_RING_ATTACH(_r, _s, _i, __size) do { \ #define FRONT_RING_ATTACH(_r, _s, _i, __size) do { \
(_r)->req_prod_pvt = (_i); \ (_r)->req_prod_pvt = (_i); \
(_r)->rsp_cons = (_i); \ (_r)->rsp_cons = (_i); \
(_r)->nr_ents = __RING_SIZE(_s, __size); \ (_r)->nr_ents = __RING_SIZE(_s, __size); \
(_r)->sring = (_s); \ (_r)->sring = (_s); \
} while (0) } while (0)
#define FRONT_RING_INIT(_r, _s, __size) FRONT_RING_ATTACH(_r, _s, 0, __size) #define FRONT_RING_INIT(_r, _s, __size) FRONT_RING_ATTACH(_r, _s, 0, __size)
#define BACK_RING_ATTACH(_r, _s, _i, __size) do { \ #define BACK_RING_ATTACH(_r, _s, _i, __size) do { \
(_r)->rsp_prod_pvt = (_i); \ (_r)->rsp_prod_pvt = (_i); \
(_r)->req_cons = (_i); \ (_r)->req_cons = (_i); \
(_r)->nr_ents = __RING_SIZE(_s, __size); \ (_r)->nr_ents = __RING_SIZE(_s, __size); \
(_r)->sring = (_s); \ (_r)->sring = (_s); \
} while (0) } while (0)
#define BACK_RING_INIT(_r, _s, __size) BACK_RING_ATTACH(_r, _s, 0, __size) #define BACK_RING_INIT(_r, _s, __size) BACK_RING_ATTACH(_r, _s, 0, __size)
/* How big is this ring? */ /* How big is this ring? */
#define RING_SIZE(_r) \ #define RING_SIZE(_r) \
((_r)->nr_ents) ((_r)->nr_ents)
/* Number of free requests (for use on front side only). */ /* Number of free requests (for use on front side only). */
#define RING_FREE_REQUESTS(_r) \ #define RING_FREE_REQUESTS(_r) \
(RING_SIZE(_r) - ((_r)->req_prod_pvt - (_r)->rsp_cons)) (RING_SIZE(_r) - ((_r)->req_prod_pvt - (_r)->rsp_cons))
/* Test if there is an empty slot available on the front ring. /* Test if there is an empty slot available on the front ring.
* (This is only meaningful from the front. ) * (This is only meaningful from the front. )
*/ */
#define RING_FULL(_r) \ #define RING_FULL(_r) \
(RING_FREE_REQUESTS(_r) == 0) (RING_FREE_REQUESTS(_r) == 0)
/* Test if there are outstanding messages to be processed on a ring. */ /* Test if there are outstanding messages to be processed on a ring. */
#define RING_HAS_UNCONSUMED_RESPONSES(_r) \ #define RING_HAS_UNCONSUMED_RESPONSES(_r) \
((_r)->sring->rsp_prod - (_r)->rsp_cons) ((_r)->sring->rsp_prod - (_r)->rsp_cons)
#define RING_HAS_UNCONSUMED_REQUESTS(_r) \ #define RING_HAS_UNCONSUMED_REQUESTS(_r) ({ \
({ \ unsigned int req = (_r)->sring->req_prod - (_r)->req_cons; \
unsigned int req = (_r)->sring->req_prod - (_r)->req_cons; \ unsigned int rsp = RING_SIZE(_r) - \
unsigned int rsp = RING_SIZE(_r) - \ ((_r)->req_cons - (_r)->rsp_prod_pvt); \
((_r)->req_cons - (_r)->rsp_prod_pvt); \ req < rsp ? req : rsp; \
req < rsp ? req : rsp; \ })
})
/* Direct access to individual ring elements, by index. */ /* Direct access to individual ring elements, by index. */
#define RING_GET_REQUEST(_r, _idx) \ #define RING_GET_REQUEST(_r, _idx) \
(&((_r)->sring->ring[((_idx) & (RING_SIZE(_r) - 1))].req)) (&((_r)->sring->ring[((_idx) & (RING_SIZE(_r) - 1))].req))
#define RING_GET_RESPONSE(_r, _idx) \
(&((_r)->sring->ring[((_idx) & (RING_SIZE(_r) - 1))].rsp))
/* /*
* Get a local copy of a request. * Get a local copy of a request/response.
* *
* Use this in preference to RING_GET_REQUEST() so all processing is * Use this in preference to RING_GET_{REQUEST,RESPONSE}() so all processing is
* done on a local copy that cannot be modified by the other end. * done on a local copy that cannot be modified by the other end.
* *
* Note that https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58145 may cause this * Note that https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58145 may cause this
* to be ineffective where _req is a struct which consists of only bitfields. * to be ineffective where dest is a struct which consists of only bitfields.
*/ */
#define RING_COPY_REQUEST(_r, _idx, _req) do { \ #define RING_COPY_(type, r, idx, dest) do { \
/* Use volatile to force the copy into _req. */ \ /* Use volatile to force the copy into dest. */ \
*(_req) = *(volatile typeof(_req))RING_GET_REQUEST(_r, _idx); \ *(dest) = *(volatile typeof(dest))RING_GET_##type(r, idx); \
} while (0) } while (0)
#define RING_GET_RESPONSE(_r, _idx) \ #define RING_COPY_REQUEST(r, idx, req) RING_COPY_(REQUEST, r, idx, req)
(&((_r)->sring->ring[((_idx) & (RING_SIZE(_r) - 1))].rsp)) #define RING_COPY_RESPONSE(r, idx, rsp) RING_COPY_(RESPONSE, r, idx, rsp)
/* Loop termination condition: Would the specified index overflow the ring? */ /* Loop termination condition: Would the specified index overflow the ring? */
#define RING_REQUEST_CONS_OVERFLOW(_r, _cons) \ #define RING_REQUEST_CONS_OVERFLOW(_r, _cons) \
(((_cons) - (_r)->rsp_prod_pvt) >= RING_SIZE(_r)) (((_cons) - (_r)->rsp_prod_pvt) >= RING_SIZE(_r))
/* Ill-behaved frontend determination: Can there be this many requests? */ /* Ill-behaved frontend determination: Can there be this many requests? */
#define RING_REQUEST_PROD_OVERFLOW(_r, _prod) \ #define RING_REQUEST_PROD_OVERFLOW(_r, _prod) \
(((_prod) - (_r)->rsp_prod_pvt) > RING_SIZE(_r)) (((_prod) - (_r)->rsp_prod_pvt) > RING_SIZE(_r))
/* Ill-behaved backend determination: Can there be this many responses? */
#define RING_RESPONSE_PROD_OVERFLOW(_r, _prod) \
(((_prod) - (_r)->rsp_cons) > RING_SIZE(_r))
#define RING_PUSH_REQUESTS(_r) do { \ #define RING_PUSH_REQUESTS(_r) do { \
virt_wmb(); /* back sees requests /before/ updated producer index */ \ virt_wmb(); /* back sees requests /before/ updated producer index */\
(_r)->sring->req_prod = (_r)->req_prod_pvt; \ (_r)->sring->req_prod = (_r)->req_prod_pvt; \
} while (0) } while (0)
#define RING_PUSH_RESPONSES(_r) do { \ #define RING_PUSH_RESPONSES(_r) do { \
virt_wmb(); /* front sees responses /before/ updated producer index */ \ virt_wmb(); /* front sees resps /before/ updated producer index */ \
(_r)->sring->rsp_prod = (_r)->rsp_prod_pvt; \ (_r)->sring->rsp_prod = (_r)->rsp_prod_pvt; \
} while (0) } while (0)
/* /*
...@@ -239,40 +273,40 @@ struct __name##_back_ring { \ ...@@ -239,40 +273,40 @@ struct __name##_back_ring { \
* field appropriately. * field appropriately.
*/ */
#define RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(_r, _notify) do { \ #define RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(_r, _notify) do { \
RING_IDX __old = (_r)->sring->req_prod; \ RING_IDX __old = (_r)->sring->req_prod; \
RING_IDX __new = (_r)->req_prod_pvt; \ RING_IDX __new = (_r)->req_prod_pvt; \
virt_wmb(); /* back sees requests /before/ updated producer index */ \ virt_wmb(); /* back sees requests /before/ updated producer index */\
(_r)->sring->req_prod = __new; \ (_r)->sring->req_prod = __new; \
virt_mb(); /* back sees new requests /before/ we check req_event */ \ virt_mb(); /* back sees new requests /before/ we check req_event */ \
(_notify) = ((RING_IDX)(__new - (_r)->sring->req_event) < \ (_notify) = ((RING_IDX)(__new - (_r)->sring->req_event) < \
(RING_IDX)(__new - __old)); \ (RING_IDX)(__new - __old)); \
} while (0) } while (0)
#define RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(_r, _notify) do { \ #define RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(_r, _notify) do { \
RING_IDX __old = (_r)->sring->rsp_prod; \ RING_IDX __old = (_r)->sring->rsp_prod; \
RING_IDX __new = (_r)->rsp_prod_pvt; \ RING_IDX __new = (_r)->rsp_prod_pvt; \
virt_wmb(); /* front sees responses /before/ updated producer index */ \ virt_wmb(); /* front sees resps /before/ updated producer index */ \
(_r)->sring->rsp_prod = __new; \ (_r)->sring->rsp_prod = __new; \
virt_mb(); /* front sees new responses /before/ we check rsp_event */ \ virt_mb(); /* front sees new resps /before/ we check rsp_event */ \
(_notify) = ((RING_IDX)(__new - (_r)->sring->rsp_event) < \ (_notify) = ((RING_IDX)(__new - (_r)->sring->rsp_event) < \
(RING_IDX)(__new - __old)); \ (RING_IDX)(__new - __old)); \
} while (0) } while (0)
#define RING_FINAL_CHECK_FOR_REQUESTS(_r, _work_to_do) do { \ #define RING_FINAL_CHECK_FOR_REQUESTS(_r, _work_to_do) do { \
(_work_to_do) = RING_HAS_UNCONSUMED_REQUESTS(_r); \ (_work_to_do) = RING_HAS_UNCONSUMED_REQUESTS(_r); \
if (_work_to_do) break; \ if (_work_to_do) break; \
(_r)->sring->req_event = (_r)->req_cons + 1; \ (_r)->sring->req_event = (_r)->req_cons + 1; \
virt_mb(); \ virt_mb(); \
(_work_to_do) = RING_HAS_UNCONSUMED_REQUESTS(_r); \ (_work_to_do) = RING_HAS_UNCONSUMED_REQUESTS(_r); \
} while (0) } while (0)
#define RING_FINAL_CHECK_FOR_RESPONSES(_r, _work_to_do) do { \ #define RING_FINAL_CHECK_FOR_RESPONSES(_r, _work_to_do) do { \
(_work_to_do) = RING_HAS_UNCONSUMED_RESPONSES(_r); \ (_work_to_do) = RING_HAS_UNCONSUMED_RESPONSES(_r); \
if (_work_to_do) break; \ if (_work_to_do) break; \
(_r)->sring->rsp_event = (_r)->rsp_cons + 1; \ (_r)->sring->rsp_event = (_r)->rsp_cons + 1; \
virt_mb(); \ virt_mb(); \
(_work_to_do) = RING_HAS_UNCONSUMED_RESPONSES(_r); \ (_work_to_do) = RING_HAS_UNCONSUMED_RESPONSES(_r); \
} while (0) } while (0)
......
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