| /* 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 |
| get_realdatapage r8, r11 |
| addi r8, r8, VDSO_RNG_DATA_OFFSET |
| 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) |
