kernel.git/arch/x86/kernel/kgdb.c, branch master

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

2025-06-24T20:15:52Z

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

2025-03-17T05:05:52Z

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

2023-09-24T09:00:13Z

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

2021-03-18T14:31:53Z

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

2020-09-04T13:12:58Z

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

2020-08-23T22:36:59Z

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

2020-06-17T17:57:41Z

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()

2019-07-25T14:12:00Z

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

2019-07-25T14:11:56Z

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

x86/stackframe/32: Provide consistent pt_regs

2019-06-25T08:23:47Z

Currently pt_regs on x86_32 has an oddity in that kernel regs (!user_mode(regs)) are short two entries (esp/ss). This means that any code trying to use them (typically: regs->sp) needs to jump through some unfortunate hoops. Change the entry code to fix this up and create a full pt_regs frame. This then simplifies various trampolines in ftrace and kprobes, the stack unwinder, ptrace, kdump and kgdb. Much thanks to Josh for help with the cleanups! Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Josh Poimboeuf Acked-by: Masami Hiramatsu Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Signed-off-by: Ingo Molnar