Cr4 tsd
WebDisabling user-space RDTSC (setting CR4.TSD) seems evil and pointless. At least some users of it (the perfctr library and I hope eventually also perfmon2) do use it in an SMP-safe manner (through special user/kernel protocols). /Mikael-To unsubscribe from this list: send the line "unsubscribe linux-kernel" in Webx86: Implement prctl PR_GET_TSC and PR_SET_TSC This patch adds a configure option CONFIG_DISABLE_TSC (off by default) for the x86 platform to enable the
Cr4 tsd
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WebWithout TSD being tagged as possibly owned by the guest, a targeted read of CR4 to get TSD could observe a stale value. This bug is benign in the current code base as the sole … WebThe time stamp disable (TSD) flag in register CR4 restricts the use of the RDTSC instruction. When the TSD flag is clear, the RDTSC instruction can be executed at any privilege level; when the flag is set, the instruction can only be executed at privilege level 0. The time-stamp counter can also be read with the RDMSR instruction, when ...
WebNov 25, 2024 · ̿ٞ k' pa i z tik + s乁 [ 4 ѿ q#w " j ! r % p/ =@a ࠵& xf hf { omj 5 дb 3 t^ u v/^ - x hn a r + ; w -3' . v jx88 㼢 x re c * @4 lc c y {: o _ $) д> t m e v >aj ie l 4âg x3 ! i i0 j x` z> ` y p m ! h u rj]z5 vwoϩ9ǒ0 ( en > rxm s}es ! ~v s[ " 99 b ik;0 5 j k7 cr4 zݵhc ( ; >7 0 a 으 \ q 1 k coa e lw kħ m j * ι p x- 6 r) oo u? i6w۫ ... WebThe time stamp disable (TSD) flag in register CR4 restricts the use of the RDTSCP instruction as follows. When the flag is clear, the RDTSCP instruction can be executed at any privilege level; when the flag is set, the instruction …
WebOp/EnOperand 1Operand 2Operand 3Operand 4 ZONANANANA 1.A load is considered to become globally visible when the value to be loaded is determined. image/svg+xml Protected Mode Exceptions #GP(0)If the TSD flag in register CR4 is set and the CPL is greater than 0. #UD If the LOCK prefix is used. Real-Address Mode Exceptions #UD If … WebAtlas Client: Atlas Web: ...
WebThe RDTSC instruction is supported, including CR4.TSD for controlling privilege. 5: MSR: Model Specific Registers RDMSR and WRMSR Instructions. The RDMSR and WRMSR instructions are supported. Some of the MSRs are implementation dependent. 6: PAE: Physical Address Extension. Physical addresses greater than 32 bits are supported: …
Web2)RDTSC can become priviledged by setting CR4.TSD flag: We can get an access violation if this instruction is used 3) Attacker cannot spend much time between RDTSC because execution time on multi core CPUs depend on things attacker cannot observe. => wait too long, too much noise to pick up signal. 4) When Clflush actually flushes an address a ... stick fiveWeb*tip: x86/iopl] x86/cpu: Unify cpu_init() @ 2024-11-16 11:51 tip-bot2 for Thomas Gleixner 0 siblings, 0 replies; 2+ messages in thread From: tip-bot2 for Thomas Gleixner @ 2024-11-16 11:51 UTC (permalink / raw) To: linux-tip-commits Cc: Thomas Gleixner, Andy Lutomirski, Ingo Molnar, Borislav Petkov, linux-kernel The following commit has been ... stick flip coordinationWebpatch: enabling RDPMC: bit 8 in CR4 (PCE) From: Tuukka Toivonen ([email protected]) Date: Thu Jan 18 2001 - 10:38:20 EST Next message: Tobias Ringstrom: "[OT] Re: rsync + ssh fail on raid; okay on 2.2.x" Previous message: Joel Franco Guzmán: "Re: PROBLEM: 128M memory OK, but with 192M sound card es1391 … stick float wizardryWeb(write_cr4) and using a helper (set/clear_in_cr4). Unfortunately, the set_in_cr4 and clear_in_cr4 helpers also poke at the boot code, which only a small subset of users actually wanted. This patch replaces all cr4 access in functions that don't leave cr4 exactly the way they found it with new helpers cr4_set, cr4_clear, and cr4_set_and_update_boot. stick flashingExtended Feature Enable Register (EFER) is a model-specific register added in the AMD K6 processor, to allow enabling the SYSCALL/SYSRET instruction, and later for entering and exiting long mode. This register becomes architectural in AMD64 and has been adopted by Intel as IA32_EFER. Its MSR number is 0xC0000080. CR8 is a new register accessible in 64-bit mode using the REX prefix. CR8 is used to prioritize … stick flash gamesWebJan 10, 2024 · • TSD flag — A control register flag is used to enable or disable the time-stamp counter (enabled if CR4.TSD[bit 2] = 1). The time-stamp counter (as implemented … stick fleas on chickensWebLinux, under CONFIG_SECCOMP, has been capable of hiding the TSC from processes for quite a while. This patch enables this to actually work for pv kernels, by allowing them to control CR4.TSD (and, as a simple thing to do at the same time, CR4.DE). Applies cleanly only on top of the previously submitted debug register handling patch. stick float or waggler