| /* SPDX-License-Identifier: GPL-2.0-or-later */ | |
| /* | |
| * Userland implementation of getrandom() for processes | |
| * for use in the vDSO | |
| * | |
| * Copyright (C) 2024 Christophe Leroy <christophe.leroy@csgroup.eu>, CS GROUP France | |
| */ | |
| #include <asm/processor.h> | |
| #include <asm/ppc_asm.h> | |
| #include <asm/vdso.h> | |
| #include <asm/vdso_datapage.h> | |
| #include <asm/asm-offsets.h> | |
| #include <asm/unistd.h> | |
| /* | |
| * The macro sets two stack frames, one for the caller and one for the callee | |
| * because there are no requirement for the caller to set a stack frame when | |
| * calling VDSO so it may have omitted to set one, especially on PPC64 | |
| */ | |
| .macro cvdso_call funct | |
| .cfi_startproc | |
| PPC_STLU r1, -PPC_MIN_STKFRM(r1) | |
| .cfi_adjust_cfa_offset PPC_MIN_STKFRM | |
| mflr r0 | |
| PPC_STLU r1, -PPC_MIN_STKFRM(r1) | |
| .cfi_adjust_cfa_offset PPC_MIN_STKFRM | |
| PPC_STL r0, PPC_MIN_STKFRM + PPC_LR_STKOFF(r1) | |
| .cfi_rel_offset lr, PPC_MIN_STKFRM + PPC_LR_STKOFF | |
| #ifdef __powerpc64__ | |
| PPC_STL r2, PPC_MIN_STKFRM + STK_GOT(r1) | |
| .cfi_rel_offset r2, PPC_MIN_STKFRM + STK_GOT | |
| #endif | |
| bl CFUNC(DOTSYM(\funct)) | |
| PPC_LL r0, PPC_MIN_STKFRM + PPC_LR_STKOFF(r1) | |
| #ifdef __powerpc64__ | |
| PPC_LL r2, PPC_MIN_STKFRM + STK_GOT(r1) | |
| .cfi_restore r2 | |
| #endif | |
| cmpwi r3, 0 | |
| mtlr r0 | |
| addi r1, r1, 2 * PPC_MIN_STKFRM | |
| .cfi_restore lr | |
| .cfi_def_cfa_offset 0 | |
| crclr so | |
| bgelr+ | |
| crset so | |
| neg r3, r3 | |
| blr | |
| .cfi_endproc | |
| .endm | |
| .text | |
| V_FUNCTION_BEGIN(__kernel_getrandom) | |
| cvdso_call __c_kernel_getrandom | |
| V_FUNCTION_END(__kernel_getrandom) |