1/* SPDX-License-Identifier: GPL-2.0-or-later */ 2/* 3 * Userland implementation of getrandom() for processes 4 * for use in the vDSO 5 * 6 * Copyright (C) 2024 Christophe Leroy <christophe.leroy@csgroup.eu>, CS GROUP France 7 */ 8#include <asm/processor.h> 9#include <asm/ppc_asm.h> 10#include <asm/vdso.h> 11#include <asm/vdso_datapage.h> 12#include <asm/asm-offsets.h> 13#include <asm/unistd.h> 14 15/* 16 * The macro sets two stack frames, one for the caller and one for the callee 17 * because there are no requirement for the caller to set a stack frame when 18 * calling VDSO so it may have omitted to set one, especially on PPC64 19 */ 20 21.macro cvdso_call funct 22 .cfi_startproc 23 PPC_STLU r1, -PPC_MIN_STKFRM(r1) 24 .cfi_adjust_cfa_offset PPC_MIN_STKFRM 25 mflr r0 26 PPC_STLU r1, -PPC_MIN_STKFRM(r1) 27 .cfi_adjust_cfa_offset PPC_MIN_STKFRM 28 PPC_STL r0, PPC_MIN_STKFRM + PPC_LR_STKOFF(r1) 29 .cfi_rel_offset lr, PPC_MIN_STKFRM + PPC_LR_STKOFF 30#ifdef __powerpc64__ 31 PPC_STL r2, PPC_MIN_STKFRM + STK_GOT(r1) 32 .cfi_rel_offset r2, PPC_MIN_STKFRM + STK_GOT 33#endif 34 bl CFUNC(DOTSYM(\funct)) 35 PPC_LL r0, PPC_MIN_STKFRM + PPC_LR_STKOFF(r1) 36#ifdef __powerpc64__ 37 PPC_LL r2, PPC_MIN_STKFRM + STK_GOT(r1) 38 .cfi_restore r2 39#endif 40 cmpwi r3, 0 41 mtlr r0 42 addi r1, r1, 2 * PPC_MIN_STKFRM 43 .cfi_restore lr 44 .cfi_def_cfa_offset 0 45 crclr so 46 bgelr+ 47 crset so 48 neg r3, r3 49 blr 50 .cfi_endproc 51.endm 52 53 .text 54V_FUNCTION_BEGIN(__kernel_getrandom) 55 cvdso_call __c_kernel_getrandom 56V_FUNCTION_END(__kernel_getrandom) 57