diff options
-rw-r--r-- | Documentation/arm64/memory.rst | 9 | ||||
-rw-r--r-- | arch/arm64/Kconfig | 15 | ||||
-rw-r--r-- | arch/arm64/Makefile | 16 | ||||
-rw-r--r-- | arch/arm64/include/asm/atomic_lse.h | 6 | ||||
-rw-r--r-- | arch/arm64/include/asm/vdso/compat_barrier.h | 2 | ||||
-rw-r--r-- | arch/arm64/include/asm/vdso_datapage.h | 33 | ||||
-rw-r--r-- | arch/arm64/kernel/armv8_deprecated.c | 5 | ||||
-rw-r--r-- | arch/arm64/kernel/cpu_errata.c | 4 | ||||
-rw-r--r-- | arch/arm64/kernel/cpufeature.c | 1 | ||||
-rw-r--r-- | arch/arm64/kernel/entry.S | 1 | ||||
-rw-r--r-- | arch/arm64/kernel/ftrace.c | 12 | ||||
-rw-r--r-- | arch/arm64/kernel/process.c | 32 | ||||
-rw-r--r-- | arch/arm64/kernel/vdso/gettimeofday.S | 0 | ||||
-rw-r--r-- | arch/arm64/kernel/vdso32/Makefile | 44 | ||||
-rw-r--r-- | arch/arm64/mm/fault.c | 13 | ||||
-rw-r--r-- | lib/vdso/Kconfig | 9 |
16 files changed, 98 insertions, 104 deletions
diff --git a/Documentation/arm64/memory.rst b/Documentation/arm64/memory.rst index b040909e45f8..02e02175e6f5 100644 --- a/Documentation/arm64/memory.rst +++ b/Documentation/arm64/memory.rst @@ -154,11 +154,18 @@ return virtual addresses to userspace from a 48-bit range. Software can "opt-in" to receiving VAs from a 52-bit space by specifying an mmap hint parameter that is larger than 48-bit. + For example: - maybe_high_address = mmap(~0UL, size, prot, flags,...); + +.. code-block:: c + + maybe_high_address = mmap(~0UL, size, prot, flags,...); It is also possible to build a debug kernel that returns addresses from a 52-bit space by enabling the following kernel config options: + +.. code-block:: sh + CONFIG_EXPERT=y && CONFIG_ARM64_FORCE_52BIT=y Note that this option is only intended for debugging applications diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 41a9b4257b72..950a56b71ff0 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -110,7 +110,6 @@ config ARM64 select GENERIC_STRNLEN_USER select GENERIC_TIME_VSYSCALL select GENERIC_GETTIMEOFDAY - select GENERIC_COMPAT_VDSO if (!CPU_BIG_ENDIAN && COMPAT) select HANDLE_DOMAIN_IRQ select HARDIRQS_SW_RESEND select HAVE_PCI @@ -1159,7 +1158,7 @@ menuconfig COMPAT if COMPAT config KUSER_HELPERS - bool "Enable kuser helpers page for 32 bit applications" + bool "Enable kuser helpers page for 32-bit applications" default y help Warning: disabling this option may break 32-bit user programs. @@ -1185,6 +1184,18 @@ config KUSER_HELPERS Say N here only if you are absolutely certain that you do not need these helpers; otherwise, the safe option is to say Y. +config COMPAT_VDSO + bool "Enable vDSO for 32-bit applications" + depends on !CPU_BIG_ENDIAN && "$(CROSS_COMPILE_COMPAT)" != "" + select GENERIC_COMPAT_VDSO + default y + help + Place in the process address space of 32-bit applications an + ELF shared object providing fast implementations of gettimeofday + and clock_gettime. + + You must have a 32-bit build of glibc 2.22 or later for programs + to seamlessly take advantage of this. menuconfig ARMV8_DEPRECATED bool "Emulate deprecated/obsolete ARMv8 instructions" diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile index 84a3d502c5a5..2c0238ce0551 100644 --- a/arch/arm64/Makefile +++ b/arch/arm64/Makefile @@ -53,22 +53,6 @@ $(warning Detected assembler with broken .inst; disassembly will be unreliable) endif endif -ifeq ($(CONFIG_GENERIC_COMPAT_VDSO), y) - CROSS_COMPILE_COMPAT ?= $(CONFIG_CROSS_COMPILE_COMPAT_VDSO:"%"=%) - - ifeq ($(CONFIG_CC_IS_CLANG), y) - $(warning CROSS_COMPILE_COMPAT is clang, the compat vDSO will not be built) - else ifeq ($(strip $(CROSS_COMPILE_COMPAT)),) - $(warning CROSS_COMPILE_COMPAT not defined or empty, the compat vDSO will not be built) - else ifeq ($(shell which $(CROSS_COMPILE_COMPAT)gcc 2> /dev/null),) - $(error $(CROSS_COMPILE_COMPAT)gcc not found, check CROSS_COMPILE_COMPAT) - else - export CROSS_COMPILE_COMPAT - export CONFIG_COMPAT_VDSO := y - compat_vdso := -DCONFIG_COMPAT_VDSO=1 - endif -endif - KBUILD_CFLAGS += -mgeneral-regs-only $(lseinstr) $(brokengasinst) \ $(compat_vdso) $(cc_has_k_constraint) KBUILD_CFLAGS += -fno-asynchronous-unwind-tables diff --git a/arch/arm64/include/asm/atomic_lse.h b/arch/arm64/include/asm/atomic_lse.h index c6bd87d2915b..574808b9df4c 100644 --- a/arch/arm64/include/asm/atomic_lse.h +++ b/arch/arm64/include/asm/atomic_lse.h @@ -321,7 +321,8 @@ static inline s64 __lse_atomic64_dec_if_positive(atomic64_t *v) } #define __CMPXCHG_CASE(w, sfx, name, sz, mb, cl...) \ -static inline u##sz __lse__cmpxchg_case_##name##sz(volatile void *ptr, \ +static __always_inline u##sz \ +__lse__cmpxchg_case_##name##sz(volatile void *ptr, \ u##sz old, \ u##sz new) \ { \ @@ -362,7 +363,8 @@ __CMPXCHG_CASE(x, , mb_, 64, al, "memory") #undef __CMPXCHG_CASE #define __CMPXCHG_DBL(name, mb, cl...) \ -static inline long __lse__cmpxchg_double##name(unsigned long old1, \ +static __always_inline long \ +__lse__cmpxchg_double##name(unsigned long old1, \ unsigned long old2, \ unsigned long new1, \ unsigned long new2, \ diff --git a/arch/arm64/include/asm/vdso/compat_barrier.h b/arch/arm64/include/asm/vdso/compat_barrier.h index fb60a88b5ed4..3fd8fd6d8fc2 100644 --- a/arch/arm64/include/asm/vdso/compat_barrier.h +++ b/arch/arm64/include/asm/vdso/compat_barrier.h @@ -20,7 +20,7 @@ #define dmb(option) __asm__ __volatile__ ("dmb " #option : : : "memory") -#if __LINUX_ARM_ARCH__ >= 8 +#if __LINUX_ARM_ARCH__ >= 8 && defined(CONFIG_AS_DMB_ISHLD) #define aarch32_smp_mb() dmb(ish) #define aarch32_smp_rmb() dmb(ishld) #define aarch32_smp_wmb() dmb(ishst) diff --git a/arch/arm64/include/asm/vdso_datapage.h b/arch/arm64/include/asm/vdso_datapage.h deleted file mode 100644 index 1f38bf330a6e..000000000000 --- a/arch/arm64/include/asm/vdso_datapage.h +++ /dev/null @@ -1,33 +0,0 @@ -/* SPDX-License-Identifier: GPL-2.0-only */ -/* - * Copyright (C) 2012 ARM Limited - */ -#ifndef __ASM_VDSO_DATAPAGE_H -#define __ASM_VDSO_DATAPAGE_H - -#ifndef __ASSEMBLY__ - -struct vdso_data { - __u64 cs_cycle_last; /* Timebase at clocksource init */ - __u64 raw_time_sec; /* Raw time */ - __u64 raw_time_nsec; - __u64 xtime_clock_sec; /* Kernel time */ - __u64 xtime_clock_nsec; - __u64 xtime_coarse_sec; /* Coarse time */ - __u64 xtime_coarse_nsec; - __u64 wtm_clock_sec; /* Wall to monotonic time */ - __u64 wtm_clock_nsec; - __u32 tb_seq_count; /* Timebase sequence counter */ - /* cs_* members must be adjacent and in this order (ldp accesses) */ - __u32 cs_mono_mult; /* NTP-adjusted clocksource multiplier */ - __u32 cs_shift; /* Clocksource shift (mono = raw) */ - __u32 cs_raw_mult; /* Raw clocksource multiplier */ - __u32 tz_minuteswest; /* Whacky timezone stuff */ - __u32 tz_dsttime; - __u32 use_syscall; - __u32 hrtimer_res; -}; - -#endif /* !__ASSEMBLY__ */ - -#endif /* __ASM_VDSO_DATAPAGE_H */ diff --git a/arch/arm64/kernel/armv8_deprecated.c b/arch/arm64/kernel/armv8_deprecated.c index 2ec09debc2bb..ca158be21f83 100644 --- a/arch/arm64/kernel/armv8_deprecated.c +++ b/arch/arm64/kernel/armv8_deprecated.c @@ -174,6 +174,9 @@ static void __init register_insn_emulation(struct insn_emulation_ops *ops) struct insn_emulation *insn; insn = kzalloc(sizeof(*insn), GFP_KERNEL); + if (!insn) + return; + insn->ops = ops; insn->min = INSN_UNDEF; @@ -233,6 +236,8 @@ static void __init register_insn_emulation_sysctl(void) insns_sysctl = kcalloc(nr_insn_emulated + 1, sizeof(*sysctl), GFP_KERNEL); + if (!insns_sysctl) + return; raw_spin_lock_irqsave(&insn_emulation_lock, flags); list_for_each_entry(insn, &insn_emulation, node) { diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c index 1e43ba5c79b7..f593f4cffc0d 100644 --- a/arch/arm64/kernel/cpu_errata.c +++ b/arch/arm64/kernel/cpu_errata.c @@ -128,8 +128,8 @@ static void install_bp_hardening_cb(bp_hardening_cb_t fn, int cpu, slot = -1; /* - * enable_smccc_arch_workaround_1() passes NULL for the hyp_vecs - * start/end if we're a guest. Skip the hyp-vectors work. + * detect_harden_bp_fw() passes NULL for the hyp_vecs start/end if + * we're a guest. Skip the hyp-vectors work. */ if (!hyp_vecs_start) { __this_cpu_write(bp_hardening_data.fn, fn); diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index 9323bcc40a58..cabebf1a7976 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -136,6 +136,7 @@ static const struct arm64_ftr_bits ftr_id_aa64isar0[] = { static const struct arm64_ftr_bits ftr_id_aa64isar1[] = { ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR1_SB_SHIFT, 4, 0), + ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR1_FRINTTS_SHIFT, 4, 0), ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_PTR_AUTH), FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR1_GPI_SHIFT, 4, 0), ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_PTR_AUTH), diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S index 84a822748c84..e304fe04b098 100644 --- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -775,6 +775,7 @@ el0_sync_compat: b.ge el0_dbg b el0_inv el0_svc_compat: + gic_prio_kentry_setup tmp=x1 mov x0, sp bl el0_svc_compat_handler b ret_to_user diff --git a/arch/arm64/kernel/ftrace.c b/arch/arm64/kernel/ftrace.c index 171773257974..06e56b470315 100644 --- a/arch/arm64/kernel/ftrace.c +++ b/arch/arm64/kernel/ftrace.c @@ -121,10 +121,16 @@ int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) /* * Ensure updated trampoline is visible to instruction - * fetch before we patch in the branch. + * fetch before we patch in the branch. Although the + * architecture doesn't require an IPI in this case, + * Neoverse-N1 erratum #1542419 does require one + * if the TLB maintenance in module_enable_ro() is + * skipped due to rodata_enabled. It doesn't seem worth + * it to make it conditional given that this is + * certainly not a fast-path. */ - __flush_icache_range((unsigned long)&dst[0], - (unsigned long)&dst[1]); + flush_icache_range((unsigned long)&dst[0], + (unsigned long)&dst[1]); } addr = (unsigned long)dst; #else /* CONFIG_ARM64_MODULE_PLTS */ diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c index a47462def04b..1fb2819fc048 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -332,22 +332,27 @@ void arch_release_task_struct(struct task_struct *tsk) fpsimd_release_task(tsk); } -/* - * src and dst may temporarily have aliased sve_state after task_struct - * is copied. We cannot fix this properly here, because src may have - * live SVE state and dst's thread_info may not exist yet, so tweaking - * either src's or dst's TIF_SVE is not safe. - * - * The unaliasing is done in copy_thread() instead. This works because - * dst is not schedulable or traceable until both of these functions - * have been called. - */ int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src) { if (current->mm) fpsimd_preserve_current_state(); *dst = *src; + /* We rely on the above assignment to initialize dst's thread_flags: */ + BUILD_BUG_ON(!IS_ENABLED(CONFIG_THREAD_INFO_IN_TASK)); + + /* + * Detach src's sve_state (if any) from dst so that it does not + * get erroneously used or freed prematurely. dst's sve_state + * will be allocated on demand later on if dst uses SVE. + * For consistency, also clear TIF_SVE here: this could be done + * later in copy_process(), but to avoid tripping up future + * maintainers it is best not to leave TIF_SVE and sve_state in + * an inconsistent state, even temporarily. + */ + dst->thread.sve_state = NULL; + clear_tsk_thread_flag(dst, TIF_SVE); + return 0; } @@ -361,13 +366,6 @@ int copy_thread(unsigned long clone_flags, unsigned long stack_start, memset(&p->thread.cpu_context, 0, sizeof(struct cpu_context)); /* - * Unalias p->thread.sve_state (if any) from the parent task - * and disable discard SVE state for p: - */ - clear_tsk_thread_flag(p, TIF_SVE); - p->thread.sve_state = NULL; - - /* * In case p was allocated the same task_struct pointer as some * other recently-exited task, make sure p is disassociated from * any cpu that may have run that now-exited task recently. diff --git a/arch/arm64/kernel/vdso/gettimeofday.S b/arch/arm64/kernel/vdso/gettimeofday.S deleted file mode 100644 index e69de29bb2d1..000000000000 --- a/arch/arm64/kernel/vdso/gettimeofday.S +++ /dev/null diff --git a/arch/arm64/kernel/vdso32/Makefile b/arch/arm64/kernel/vdso32/Makefile index 1fba0776ed40..76b327f88fbb 100644 --- a/arch/arm64/kernel/vdso32/Makefile +++ b/arch/arm64/kernel/vdso32/Makefile @@ -8,15 +8,21 @@ ARCH_REL_TYPE_ABS := R_ARM_JUMP_SLOT|R_ARM_GLOB_DAT|R_ARM_ABS32 include $(srctree)/lib/vdso/Makefile -COMPATCC := $(CROSS_COMPILE_COMPAT)gcc +# Same as cc-*option, but using CC_COMPAT instead of CC +ifeq ($(CONFIG_CC_IS_CLANG), y) +CC_COMPAT ?= $(CC) +else +CC_COMPAT ?= $(CROSS_COMPILE_COMPAT)gcc +endif -# Same as cc-*option, but using COMPATCC instead of CC cc32-option = $(call try-run,\ - $(COMPATCC) $(1) -c -x c /dev/null -o "$$TMP",$(1),$(2)) + $(CC_COMPAT) $(1) -c -x c /dev/null -o "$$TMP",$(1),$(2)) cc32-disable-warning = $(call try-run,\ - $(COMPATCC) -W$(strip $(1)) -c -x c /dev/null -o "$$TMP",-Wno-$(strip $(1))) + $(CC_COMPAT) -W$(strip $(1)) -c -x c /dev/null -o "$$TMP",-Wno-$(strip $(1))) cc32-ldoption = $(call try-run,\ - $(COMPATCC) $(1) -nostdlib -x c /dev/null -o "$$TMP",$(1),$(2)) + $(CC_COMPAT) $(1) -nostdlib -x c /dev/null -o "$$TMP",$(1),$(2)) +cc32-as-instr = $(call try-run,\ + printf "%b\n" "$(1)" | $(CC_COMPAT) $(VDSO_AFLAGS) -c -x assembler -o "$$TMP" -,$(2),$(3)) # We cannot use the global flags to compile the vDSO files, the main reason # being that the 32-bit compiler may be older than the main (64-bit) compiler @@ -25,22 +31,21 @@ cc32-ldoption = $(call try-run,\ # arm64 one. # As a result we set our own flags here. -# From top-level Makefile -# NOSTDINC_FLAGS -VDSO_CPPFLAGS := -nostdinc -isystem $(shell $(COMPATCC) -print-file-name=include) +# KBUILD_CPPFLAGS and NOSTDINC_FLAGS from top-level Makefile +VDSO_CPPFLAGS := -D__KERNEL__ -nostdinc -isystem $(shell $(CC_COMPAT) -print-file-name=include) VDSO_CPPFLAGS += $(LINUXINCLUDE) -VDSO_CPPFLAGS += $(KBUILD_CPPFLAGS) # Common C and assembly flags # From top-level Makefile VDSO_CAFLAGS := $(VDSO_CPPFLAGS) +ifneq ($(shell $(CC_COMPAT) --version 2>&1 | head -n 1 | grep clang),) +VDSO_CAFLAGS += --target=$(notdir $(CROSS_COMPILE_COMPAT:%-=%)) +endif + VDSO_CAFLAGS += $(call cc32-option,-fno-PIE) ifdef CONFIG_DEBUG_INFO VDSO_CAFLAGS += -g endif -ifeq ($(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-goto.sh $(COMPATCC)), y) -VDSO_CAFLAGS += -DCC_HAVE_ASM_GOTO -endif # From arm Makefile VDSO_CAFLAGS += $(call cc32-option,-fno-dwarf2-cfi-asm) @@ -55,6 +60,7 @@ endif VDSO_CAFLAGS += -fPIC -fno-builtin -fno-stack-protector VDSO_CAFLAGS += -DDISABLE_BRANCH_PROFILING + # Try to compile for ARMv8. If the compiler is too old and doesn't support it, # fall back to v7. There is no easy way to check for what architecture the code # is being compiled, so define a macro specifying that (see arch/arm/Makefile). @@ -91,6 +97,12 @@ VDSO_CFLAGS += -Wno-int-to-pointer-cast VDSO_AFLAGS := $(VDSO_CAFLAGS) VDSO_AFLAGS += -D__ASSEMBLY__ +# Check for binutils support for dmb ishld +dmbinstr := $(call cc32-as-instr,dmb ishld,-DCONFIG_AS_DMB_ISHLD=1) + +VDSO_CFLAGS += $(dmbinstr) +VDSO_AFLAGS += $(dmbinstr) + VDSO_LDFLAGS := $(VDSO_CPPFLAGS) # From arm vDSO Makefile VDSO_LDFLAGS += -Wl,-Bsymbolic -Wl,--no-undefined -Wl,-soname=linux-vdso.so.1 @@ -159,14 +171,14 @@ quiet_cmd_vdsold_and_vdso_check = LD32 $@ cmd_vdsold_and_vdso_check = $(cmd_vdsold); $(cmd_vdso_check) quiet_cmd_vdsold = LD32 $@ - cmd_vdsold = $(COMPATCC) -Wp,-MD,$(depfile) $(VDSO_LDFLAGS) \ + cmd_vdsold = $(CC_COMPAT) -Wp,-MD,$(depfile) $(VDSO_LDFLAGS) \ -Wl,-T $(filter %.lds,$^) $(filter %.o,$^) -o $@ quiet_cmd_vdsocc = CC32 $@ - cmd_vdsocc = $(COMPATCC) -Wp,-MD,$(depfile) $(VDSO_CFLAGS) -c -o $@ $< + cmd_vdsocc = $(CC_COMPAT) -Wp,-MD,$(depfile) $(VDSO_CFLAGS) -c -o $@ $< quiet_cmd_vdsocc_gettimeofday = CC32 $@ - cmd_vdsocc_gettimeofday = $(COMPATCC) -Wp,-MD,$(depfile) $(VDSO_CFLAGS) $(VDSO_CFLAGS_gettimeofday_o) -c -o $@ $< + cmd_vdsocc_gettimeofday = $(CC_COMPAT) -Wp,-MD,$(depfile) $(VDSO_CFLAGS) $(VDSO_CFLAGS_gettimeofday_o) -c -o $@ $< quiet_cmd_vdsoas = AS32 $@ - cmd_vdsoas = $(COMPATCC) -Wp,-MD,$(depfile) $(VDSO_AFLAGS) -c -o $@ $< + cmd_vdsoas = $(CC_COMPAT) -Wp,-MD,$(depfile) $(VDSO_AFLAGS) -c -o $@ $< quiet_cmd_vdsomunge = MUNGE $@ cmd_vdsomunge = $(obj)/$(munge) $< $@ diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c index 115d7a0e4b08..855f2a7954e6 100644 --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -113,6 +113,15 @@ static inline bool is_ttbr1_addr(unsigned long addr) return arch_kasan_reset_tag(addr) >= PAGE_OFFSET; } +static inline unsigned long mm_to_pgd_phys(struct mm_struct *mm) +{ + /* Either init_pg_dir or swapper_pg_dir */ + if (mm == &init_mm) + return __pa_symbol(mm->pgd); + + return (unsigned long)virt_to_phys(mm->pgd); +} + /* * Dump out the page tables associated with 'addr' in the currently active mm. */ @@ -141,7 +150,7 @@ static void show_pte(unsigned long addr) pr_alert("%s pgtable: %luk pages, %llu-bit VAs, pgdp=%016lx\n", mm == &init_mm ? "swapper" : "user", PAGE_SIZE / SZ_1K, - vabits_actual, (unsigned long)virt_to_phys(mm->pgd)); + vabits_actual, mm_to_pgd_phys(mm)); pgdp = pgd_offset(mm, addr); pgd = READ_ONCE(*pgdp); pr_alert("[%016lx] pgd=%016llx", addr, pgd_val(pgd)); @@ -266,7 +275,7 @@ static bool __kprobes is_spurious_el1_translation_fault(unsigned long addr, * If we got a different type of fault from the AT instruction, * treat the translation fault as spurious. */ - dfsc = FIELD_PREP(SYS_PAR_EL1_FST, par); + dfsc = FIELD_GET(SYS_PAR_EL1_FST, par); return (dfsc & ESR_ELx_FSC_TYPE) != ESR_ELx_FSC_FAULT; } diff --git a/lib/vdso/Kconfig b/lib/vdso/Kconfig index cc00364bd2c2..9fe698ff62ec 100644 --- a/lib/vdso/Kconfig +++ b/lib/vdso/Kconfig @@ -24,13 +24,4 @@ config GENERIC_COMPAT_VDSO help This config option enables the compat VDSO layer. -config CROSS_COMPILE_COMPAT_VDSO - string "32 bit Toolchain prefix for compat vDSO" - default "" - depends on GENERIC_COMPAT_VDSO - help - Defines the cross-compiler prefix for compiling compat vDSO. - If a 64 bit compiler (i.e. x86_64) can compile the VDSO for - 32 bit, it does not need to define this parameter. - endif |