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- /* 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)
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