1*43033bc6SNathan Lynch /* SPDX-License-Identifier: GPL-2.0-only */ 2*43033bc6SNathan Lynch #ifndef _ASM_POWERPC_RTAS_WORK_AREA_H 3*43033bc6SNathan Lynch #define _ASM_POWERPC_RTAS_WORK_AREA_H 4*43033bc6SNathan Lynch 5*43033bc6SNathan Lynch #include <linux/build_bug.h> 6*43033bc6SNathan Lynch #include <linux/sizes.h> 7*43033bc6SNathan Lynch #include <linux/types.h> 8*43033bc6SNathan Lynch 9*43033bc6SNathan Lynch #include <asm/page.h> 10*43033bc6SNathan Lynch 11*43033bc6SNathan Lynch /** 12*43033bc6SNathan Lynch * struct rtas_work_area - RTAS work area descriptor. 13*43033bc6SNathan Lynch * 14*43033bc6SNathan Lynch * Descriptor for a "work area" in PAPR terminology that satisfies 15*43033bc6SNathan Lynch * RTAS addressing requirements. 16*43033bc6SNathan Lynch */ 17*43033bc6SNathan Lynch struct rtas_work_area { 18*43033bc6SNathan Lynch /* private: Use the APIs provided below. */ 19*43033bc6SNathan Lynch char *buf; 20*43033bc6SNathan Lynch size_t size; 21*43033bc6SNathan Lynch }; 22*43033bc6SNathan Lynch 23*43033bc6SNathan Lynch enum { 24*43033bc6SNathan Lynch /* Maximum allocation size, enforced at build time. */ 25*43033bc6SNathan Lynch RTAS_WORK_AREA_MAX_ALLOC_SZ = SZ_128K, 26*43033bc6SNathan Lynch }; 27*43033bc6SNathan Lynch 28*43033bc6SNathan Lynch /** 29*43033bc6SNathan Lynch * rtas_work_area_alloc() - Acquire a work area of the requested size. 30*43033bc6SNathan Lynch * @size_: Allocation size. Must be compile-time constant and not more 31*43033bc6SNathan Lynch * than %RTAS_WORK_AREA_MAX_ALLOC_SZ. 32*43033bc6SNathan Lynch * 33*43033bc6SNathan Lynch * Allocate a buffer suitable for passing to RTAS functions that have 34*43033bc6SNathan Lynch * a memory address parameter, often (but not always) referred to as a 35*43033bc6SNathan Lynch * "work area" in PAPR. Although callers are allowed to block while 36*43033bc6SNathan Lynch * holding a work area, the amount of memory reserved for this purpose 37*43033bc6SNathan Lynch * is limited, and allocations should be short-lived. A good guideline 38*43033bc6SNathan Lynch * is to release any allocated work area before returning from a 39*43033bc6SNathan Lynch * system call. 40*43033bc6SNathan Lynch * 41*43033bc6SNathan Lynch * This function does not fail. It blocks until the allocation 42*43033bc6SNathan Lynch * succeeds. To prevent deadlocks, callers are discouraged from 43*43033bc6SNathan Lynch * allocating more than one work area simultaneously in a single task 44*43033bc6SNathan Lynch * context. 45*43033bc6SNathan Lynch * 46*43033bc6SNathan Lynch * Context: This function may sleep. 47*43033bc6SNathan Lynch * Return: A &struct rtas_work_area descriptor for the allocated work area. 48*43033bc6SNathan Lynch */ 49*43033bc6SNathan Lynch #define rtas_work_area_alloc(size_) ({ \ 50*43033bc6SNathan Lynch static_assert(__builtin_constant_p(size_)); \ 51*43033bc6SNathan Lynch static_assert((size_) > 0); \ 52*43033bc6SNathan Lynch static_assert((size_) <= RTAS_WORK_AREA_MAX_ALLOC_SZ); \ 53*43033bc6SNathan Lynch __rtas_work_area_alloc(size_); \ 54*43033bc6SNathan Lynch }) 55*43033bc6SNathan Lynch 56*43033bc6SNathan Lynch /* 57*43033bc6SNathan Lynch * Do not call __rtas_work_area_alloc() directly. Use 58*43033bc6SNathan Lynch * rtas_work_area_alloc(). 59*43033bc6SNathan Lynch */ 60*43033bc6SNathan Lynch struct rtas_work_area *__rtas_work_area_alloc(size_t size); 61*43033bc6SNathan Lynch 62*43033bc6SNathan Lynch /** 63*43033bc6SNathan Lynch * rtas_work_area_free() - Release a work area. 64*43033bc6SNathan Lynch * @area: Work area descriptor as returned from rtas_work_area_alloc(). 65*43033bc6SNathan Lynch * 66*43033bc6SNathan Lynch * Return a work area buffer to the pool. 67*43033bc6SNathan Lynch */ 68*43033bc6SNathan Lynch void rtas_work_area_free(struct rtas_work_area *area); 69*43033bc6SNathan Lynch rtas_work_area_raw_buf(const struct rtas_work_area * area)70*43033bc6SNathan Lynchstatic inline char *rtas_work_area_raw_buf(const struct rtas_work_area *area) 71*43033bc6SNathan Lynch { 72*43033bc6SNathan Lynch return area->buf; 73*43033bc6SNathan Lynch } 74*43033bc6SNathan Lynch rtas_work_area_size(const struct rtas_work_area * area)75*43033bc6SNathan Lynchstatic inline size_t rtas_work_area_size(const struct rtas_work_area *area) 76*43033bc6SNathan Lynch { 77*43033bc6SNathan Lynch return area->size; 78*43033bc6SNathan Lynch } 79*43033bc6SNathan Lynch rtas_work_area_phys(const struct rtas_work_area * area)80*43033bc6SNathan Lynchstatic inline phys_addr_t rtas_work_area_phys(const struct rtas_work_area *area) 81*43033bc6SNathan Lynch { 82*43033bc6SNathan Lynch return __pa(area->buf); 83*43033bc6SNathan Lynch } 84*43033bc6SNathan Lynch 85*43033bc6SNathan Lynch /* 86*43033bc6SNathan Lynch * Early setup for the work area allocator. Call from 87*43033bc6SNathan Lynch * rtas_initialize() only. 88*43033bc6SNathan Lynch */ 89*43033bc6SNathan Lynch 90*43033bc6SNathan Lynch #ifdef CONFIG_PPC_PSERIES 91*43033bc6SNathan Lynch void rtas_work_area_reserve_arena(phys_addr_t limit); 92*43033bc6SNathan Lynch #else /* CONFIG_PPC_PSERIES */ rtas_work_area_reserve_arena(phys_addr_t limit)93*43033bc6SNathan Lynchstatic inline void rtas_work_area_reserve_arena(phys_addr_t limit) {} 94*43033bc6SNathan Lynch #endif /* CONFIG_PPC_PSERIES */ 95*43033bc6SNathan Lynch 96*43033bc6SNathan Lynch #endif /* _ASM_POWERPC_RTAS_WORK_AREA_H */ 97