lwn.git/arch/x86/kernel/kgdb.c, branch docs-next

kgdb: update outdated references to kgdb_wait()

2026-04-21T15:41:54+00:00

The function kgdb_wait() was folded into the static function kgdb_cpu_enter() by commit 62fae312197a ("kgdb: eliminate kgdb_wait(), all cpus enter the same way"). Update the four stale references accordingly: - include/linux/kgdb.h and arch/x86/kernel/kgdb.c: the kgdb_roundup_cpus() kdoc describes what other CPUs are rounded up to call. Because kgdb_cpu_enter() is static, the correct public entry point is kgdb_handle_exception(); also fix a pre-existing grammar error ("get them be" -> "get them into") and reflow the text. - kernel/debug/debug_core.c: replace with the generic description "the debug trap handler", since the actual entry path is architecture-specific. - kernel/debug/gdbstub.c: kgdb_cpu_enter() is correct here (it describes internal state, not a call target); add the missing parentheses. Suggested-by: Daniel Thompson Assisted-by: unnamed:deepseek-v3.2 coccinelle Signed-off-by: Kexin Sun

x86/traps: Initialize DR7 by writing its architectural reset value

2025-06-24T20:15:52+00:00

Initialize DR7 by writing its architectural reset value to always set bit 10, which is reserved to '1', when "clearing" DR7 so as not to trigger unanticipated behavior if said bit is ever unreserved, e.g. as a feature enabling flag with inverted polarity. Signed-off-by: Xin Li (Intel) Signed-off-by: Dave Hansen Reviewed-by: H. Peter Anvin (Intel) Reviewed-by: Sohil Mehta Acked-by: Peter Zijlstra (Intel) Acked-by: Sean Christopherson Tested-by: Sohil Mehta Cc:stable@vger.kernel.org Link: https://lore.kernel.org/all/20250620231504.2676902-3-xin%40zytor.com

x86/kgdb: use IS_ERR_PCPU() macro

2025-03-17T05:05:52+00:00

Patch series "Enable strict percpu address space checks", v4. Enable strict percpu address space checks via x86 named address space qualifiers. Percpu variables are declared in __seg_gs/__seg_fs named AS and kept named AS qualified until they are dereferenced via percpu accessor. This approach enables various compiler checks for cross-namespace variable assignments. Please note that current version of sparse doesn't know anything about __typeof_unqual__() operator. Avoid the usage of __typeof_unqual__() when sparse checking is active to prevent sparse errors with unknowing keyword. The proposed patch by Dan Carpenter to implement __typeof_unqual__() handling in sparse is located at: https://lore.kernel.org/lkml/5b8d0dee-8fb6-45af-ba6c-7f74aff9a4b8@stanley.mountain/ This patch (of 6): Use IS_ERR_PCPU() when checking the error pointer in the percpu address space. This macro adds intermediate cast to unsigned long when switching named address spaces. The patch will avoid future build errors due to pointer address space mismatch with enabled strict percpu address space checks. Link: https://lkml.kernel.org/r/20250127160709.80604-1-ubizjak@gmail.com Link: https://lkml.kernel.org/r/20250127160709.80604-2-ubizjak@gmail.com Signed-off-by: Uros Bizjak Acked-by: Nadav Amit Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Borislav Petkov Cc: Dave Hansen Cc: "H. Peter Anvin" Cc: Dennis Zhou Cc: Tejun Heo Cc: Christoph Lameter Cc: Linus Torvalds Cc: Andy Lutomirski Cc: Brian Gerst Cc: Peter Zijlstra Cc: Arnd Bergmann Cc: Boqun Feng Cc: "David S. Miller" Cc: Denys Vlasenko Cc: Eric Dumazet Cc: Jakub Kicinski Cc: Kent Overstreet Cc: Paolo Abeni Cc: Waiman Long Cc: Will Deacon Signed-off-by: Andrew Morton

x86/kgdb: Fix a kerneldoc warning when build with W=1

2023-09-24T09:00:13+00:00

When compiled with W=1, the following warning is generated: arch/x86/kernel/kgdb.c:698: warning: Cannot understand * on line 698 - I thought it was a doc line Remove the corresponding empty comment line to fix the warning. Signed-off-by: Christophe JAILLET Signed-off-by: Ingo Molnar Acked-by: Randy Dunlap Link: https://lore.kernel.org/r/aad659537c1d4ebd86912a6f0be458676c8e69af.1695401178.git.christophe.jaillet@wanadoo.fr

x86: Fix various typos in comments

2021-03-18T14:31:53+00:00

Fix ~144 single-word typos in arch/x86/ code comments. Doing this in a single commit should reduce the churn. Signed-off-by: Ingo Molnar Cc: Borislav Petkov Cc: Thomas Gleixner Cc: Peter Zijlstra Cc: Paolo Bonzini Cc: Bjorn Helgaas Cc: linux-kernel@vger.kernel.org

x86/debug: Change thread.debugreg6 to thread.virtual_dr6

2020-09-04T13:12:58+00:00

Current usage of thread.debugreg6 is convoluted at best. It starts life as a copy of the hardware DR6 value, but then various bits are cleared and set. Replace this with a new variable thread.virtual_dr6 that is initialized to 0 when DR6 is read and only gains bits, at the same time the actual (on stack) dr6 value which is read from the hardware only gets bits cleared. Suggested-by: Andy Lutomirski Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Thomas Gleixner Tested-by: Daniel Thompson Link: https://lore.kernel.org/r/20200902133201.415372940@infradead.org

treewide: Use fallthrough pseudo-keyword

2020-08-23T22:36:59+00:00

Replace the existing /* fall through */ comments and its variants with the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary fall-through markings when it is the case. [1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through Signed-off-by: Gustavo A. R. Silva

maccess: rename probe_kernel_{read,write} to copy_{from,to}_kernel_nofault

2020-06-17T17:57:41+00:00

Better describe what these functions do. Suggested-by: Linus Torvalds Signed-off-by: Christoph Hellwig Signed-off-by: Linus Torvalds

x86/apic: Provide and use helper for send_IPI_allbutself()

2019-07-25T14:12:00+00:00

To support IPI shorthands wrap invocations of apic->send_IPI_allbutself() in a helper function, so the static key controlling the shorthand mode is only in one place. Fixup all callers. Signed-off-by: Thomas Gleixner Acked-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20190722105220.492691679@linutronix.de

x86/kgbd: Use NMI_VECTOR not APIC_DM_NMI

2019-07-25T14:11:56+00:00

apic->send_IPI_allbutself() takes a vector number as argument. APIC_DM_NMI is clearly not a vector number. It's defined to 0x400 which is outside the vector space. Use NMI_VECTOR instead as that's what it is intended to be. Fixes: 82da3ff89dc2 ("x86: kgdb support") Signed-off-by: Thomas Gleixner Acked-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20190722105218.855189979@linutronix.de