arch/x86/entry/entry_fred.c | 22 +++++++++++++++++ arch/x86/include/asm/processor.h | 38 +++++++++++++++++++++++------- arch/x86/include/asm/switch_to.h | 2 +- arch/x86/include/asm/thread_info.h | 19 +++++---------- arch/x86/kernel/process.c | 21 +++++++++++++++++ arch/x86/kernel/vmlinux.lds.S | 18 ++++++++++++-- include/linux/thread_info.h | 1 + kernel/fork.c | 6 +++++ 8 files changed, 102 insertions(+), 25 deletions(-)
This was initially posted as part of the FRED patch series and turned down due to its unacceptable quality: https://lore.kernel.org/lkml/20230410081438.1750-31-xin3.li@intel.com/ And this is another attempt to meet the bar. a FRED event frame could contain different amount of information for different event types, e.g., #MCE could push extra bytes of information, or perhaps even for different instances of the same event type. Thus the size of an event frame pushed by a FRED CPU is not fixed and the address of a pt_regs structure that is used to save the user level context of current task is not at a fixed offset from top of current task kernel stack. This patch set adds a new field named 'user_pt_regs' in the thread_info structure to save the address of user level context pt_regs structure, thus to eliminate the need of any advance information of event frame size and allow a FRED CPU to push variable-sized event frame. With the above change, we can 1) Remove the padding space at top of the init stack because there is no user level context for init task. 2) Get rid of TOP_OF_KERNEL_STACK_PADDING on x86_64, which was defined to 0 for IDT to keep the code consistent with 32bit. Xin Li (Intel) (3): x86/fred: Allow variable-sized event frame x86: Remove the padding space at top of the init stack x86: Get rid of TOP_OF_KERNEL_STACK_PADDING on x86_64 arch/x86/entry/entry_fred.c | 22 +++++++++++++++++ arch/x86/include/asm/processor.h | 38 +++++++++++++++++++++++------- arch/x86/include/asm/switch_to.h | 2 +- arch/x86/include/asm/thread_info.h | 19 +++++---------- arch/x86/kernel/process.c | 21 +++++++++++++++++ arch/x86/kernel/vmlinux.lds.S | 18 ++++++++++++-- include/linux/thread_info.h | 1 + kernel/fork.c | 6 +++++ 8 files changed, 102 insertions(+), 25 deletions(-) base-commit: 49b33979e3bf0a5424420d14f026de12f34e8b1e -- 2.45.1
On 6/17/2024 1:45 AM, Xin Li (Intel) wrote: > This was initially posted as part of the FRED patch series and turned > down due to its unacceptable quality: > https://lore.kernel.org/lkml/20230410081438.1750-31-xin3.li@intel.com/ > > And this is another attempt to meet the bar. > I'm expecting to get some review comments on this patch set :-) > > a FRED event frame could contain different amount of information for > different event types, e.g., #MCE could push extra bytes of information, > or perhaps even for different instances of the same event type. Thus > the size of an event frame pushed by a FRED CPU is not fixed and the > address of a pt_regs structure that is used to save the user level > context of current task is not at a fixed offset from top of current > task kernel stack. > > This patch set adds a new field named 'user_pt_regs' in the thread_info > structure to save the address of user level context pt_regs structure, > thus to eliminate the need of any advance information of event frame > size and allow a FRED CPU to push variable-sized event frame. > > With the above change, we can > 1) Remove the padding space at top of the init stack because there is > no user level context for init task. > 2) Get rid of TOP_OF_KERNEL_STACK_PADDING on x86_64, which was defined > to 0 for IDT to keep the code consistent with 32bit. > > > Xin Li (Intel) (3): > x86/fred: Allow variable-sized event frame > x86: Remove the padding space at top of the init stack > x86: Get rid of TOP_OF_KERNEL_STACK_PADDING on x86_64 > > arch/x86/entry/entry_fred.c | 22 +++++++++++++++++ > arch/x86/include/asm/processor.h | 38 +++++++++++++++++++++++------- > arch/x86/include/asm/switch_to.h | 2 +- > arch/x86/include/asm/thread_info.h | 19 +++++---------- > arch/x86/kernel/process.c | 21 +++++++++++++++++ > arch/x86/kernel/vmlinux.lds.S | 18 ++++++++++++-- > include/linux/thread_info.h | 1 + > kernel/fork.c | 6 +++++ > 8 files changed, 102 insertions(+), 25 deletions(-) > > > base-commit: 49b33979e3bf0a5424420d14f026de12f34e8b1e
On 8/26/2024 10:32 AM, Xin Li wrote: > On 6/17/2024 1:45 AM, Xin Li (Intel) wrote: >> This was initially posted as part of the FRED patch series and turned >> down due to its unacceptable quality: >> https://lore.kernel.org/lkml/20230410081438.1750-31-xin3.li@intel.com/ >> >> And this is another attempt to meet the bar. >> > > I'm expecting to get some review comments on this patch set :-) Try to get some reviews again :) > >> >> a FRED event frame could contain different amount of information for >> different event types, e.g., #MCE could push extra bytes of information, >> or perhaps even for different instances of the same event type. Thus >> the size of an event frame pushed by a FRED CPU is not fixed and the >> address of a pt_regs structure that is used to save the user level >> context of current task is not at a fixed offset from top of current >> task kernel stack. >> >> This patch set adds a new field named 'user_pt_regs' in the thread_info >> structure to save the address of user level context pt_regs structure, >> thus to eliminate the need of any advance information of event frame >> size and allow a FRED CPU to push variable-sized event frame. >> >> With the above change, we can >> 1) Remove the padding space at top of the init stack because there is >> no user level context for init task. >> 2) Get rid of TOP_OF_KERNEL_STACK_PADDING on x86_64, which was defined >> to 0 for IDT to keep the code consistent with 32bit. >> >> >> Xin Li (Intel) (3): >> x86/fred: Allow variable-sized event frame >> x86: Remove the padding space at top of the init stack >> x86: Get rid of TOP_OF_KERNEL_STACK_PADDING on x86_64 >> >> arch/x86/entry/entry_fred.c | 22 +++++++++++++++++ >> arch/x86/include/asm/processor.h | 38 +++++++++++++++++++++++------- >> arch/x86/include/asm/switch_to.h | 2 +- >> arch/x86/include/asm/thread_info.h | 19 +++++---------- >> arch/x86/kernel/process.c | 21 +++++++++++++++++ >> arch/x86/kernel/vmlinux.lds.S | 18 ++++++++++++-- >> include/linux/thread_info.h | 1 + >> kernel/fork.c | 6 +++++ >> 8 files changed, 102 insertions(+), 25 deletions(-) >> >> >> base-commit: 49b33979e3bf0a5424420d14f026de12f34e8b1e > >
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