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https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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8072b39c3a
Extend getrandom() vDSO implementation to VDSO64. Tested on QEMU on both ppc64_defconfig and ppc64le_defconfig. Results from a Power9 (PowerNV): ~ # ./vdso_test_getrandom bench-single vdso: 25000000 times in 0.787943615 seconds libc: 25000000 times in 14.101887252 seconds syscall: 25000000 times in 14.047475082 seconds Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Tested-by: Madhavan Srinivasan <maddy@linux.ibm.com> Acked-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
59 lines
1.5 KiB
ArmAsm
59 lines
1.5 KiB
ArmAsm
/* SPDX-License-Identifier: GPL-2.0-or-later */
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/*
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* Userland implementation of getrandom() for processes
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* for use in the vDSO
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*
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* Copyright (C) 2024 Christophe Leroy <christophe.leroy@csgroup.eu>, CS GROUP France
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*/
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#include <asm/processor.h>
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#include <asm/ppc_asm.h>
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#include <asm/vdso.h>
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#include <asm/vdso_datapage.h>
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#include <asm/asm-offsets.h>
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#include <asm/unistd.h>
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/*
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* The macro sets two stack frames, one for the caller and one for the callee
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* because there are no requirement for the caller to set a stack frame when
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* calling VDSO so it may have omitted to set one, especially on PPC64
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*/
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.macro cvdso_call funct
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.cfi_startproc
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PPC_STLU r1, -PPC_MIN_STKFRM(r1)
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.cfi_adjust_cfa_offset PPC_MIN_STKFRM
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mflr r0
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PPC_STLU r1, -PPC_MIN_STKFRM(r1)
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.cfi_adjust_cfa_offset PPC_MIN_STKFRM
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PPC_STL r0, PPC_MIN_STKFRM + PPC_LR_STKOFF(r1)
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.cfi_rel_offset lr, PPC_MIN_STKFRM + PPC_LR_STKOFF
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#ifdef __powerpc64__
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PPC_STL r2, PPC_MIN_STKFRM + STK_GOT(r1)
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.cfi_rel_offset r2, PPC_MIN_STKFRM + STK_GOT
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#endif
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get_realdatapage r8, r11
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addi r8, r8, VDSO_RNG_DATA_OFFSET
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bl CFUNC(DOTSYM(\funct))
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PPC_LL r0, PPC_MIN_STKFRM + PPC_LR_STKOFF(r1)
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#ifdef __powerpc64__
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PPC_LL r2, PPC_MIN_STKFRM + STK_GOT(r1)
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.cfi_restore r2
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#endif
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cmpwi r3, 0
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mtlr r0
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addi r1, r1, 2 * PPC_MIN_STKFRM
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.cfi_restore lr
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.cfi_def_cfa_offset 0
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crclr so
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bgelr+
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crset so
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neg r3, r3
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blr
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.cfi_endproc
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.endm
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.text
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V_FUNCTION_BEGIN(__kernel_getrandom)
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cvdso_call __c_kernel_getrandom
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V_FUNCTION_END(__kernel_getrandom)
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