From: "Jan Beulich" <JBeulich@suse.com>
To: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Keir Fraser <keir@xen.org>,
ross.lagerwall@citrix.com, andrew.cooper3@citrix.com,
mpohlack@amazon.de, Julien Grall <julien.grall@arm.com>,
Stefano Stabellini <stefano.stabellini@citrix.com>,
sasha.levin@oracle.com, xen-devel@lists.xenproject.org
Subject: Re: [PATCH v4 07/34] arm/x86: Use struct virtual_region to do bug, symbol, and (x86) exception tables
Date: Fri, 18 Mar 2016 07:07:19 -0600 [thread overview]
Message-ID: <56EC0B9702000078000DE5A6@prv-mh.provo.novell.com> (raw)
In-Reply-To: <1458064616-23101-8-git-send-email-konrad.wilk@oracle.com>
>>> On 15.03.16 at 18:56, <konrad.wilk@oracle.com> wrote:
> lookup.
Was this meant to be part of $subject?
> @@ -1077,27 +1080,39 @@ void do_unexpected_trap(const char *msg, struct
> cpu_user_regs *regs)
>
> int do_bug_frame(struct cpu_user_regs *regs, vaddr_t pc)
> {
> - const struct bug_frame *bug;
> + const struct bug_frame *bug = NULL;
> const char *prefix = "", *filename, *predicate;
> unsigned long fixup;
> - int id, lineno;
> - static const struct bug_frame *const stop_frames[] = {
> - __stop_bug_frames_0,
> - __stop_bug_frames_1,
> - __stop_bug_frames_2,
> - NULL
> - };
> + int id = -1, lineno;
> + struct virtual_region *region;
>
> - for ( bug = __start_bug_frames, id = 0; stop_frames[id]; ++bug )
> + list_for_each_entry( region, &virtual_region_list, list )
> {
> - while ( unlikely(bug == stop_frames[id]) )
> - ++id;
> + unsigned int i;
>
> - if ( ((vaddr_t)bug_loc(bug)) == pc )
> - break;
> - }
> + if ( region->skip && region->skip(CHECKING_BUG_FRAME, region->priv) )
> + continue;
> +
> + if ( pc < region->start || pc > region->end )
> + continue;
>
> - if ( !stop_frames[id] )
> + for ( id = 0; id < BUGFRAME_NR; id++ )
> + {
> + const struct bug_frame *b = NULL;
Pointless initializer.
> --- a/xen/arch/x86/extable.c
> +++ b/xen/arch/x86/extable.c
> @@ -1,6 +1,8 @@
>
> +#include <xen/bug_ex_symbols.h>
> #include <xen/config.h>
In cases like this please take the opportunity to get rid of the
explicit inclusion of xen/config.h.
> --- /dev/null
> +++ b/xen/common/bug_ex_symbols.c
> @@ -0,0 +1,119 @@
> +/*
> + * Copyright (c) 2016 Oracle and/or its affiliates. All rights reserved.
> + *
> + */
> +
> +#include <xen/bug_ex_symbols.h>
> +#include <xen/config.h>
> +#include <xen/kernel.h>
> +#include <xen/init.h>
> +#include <xen/spinlock.h>
> +
> +extern char __stext[];
> +
> +struct virtual_region kernel_text = {
static
> + .list = LIST_HEAD_INIT(kernel_text.list),
> + .start = (unsigned long)_stext,
> + .end = (unsigned long)_etext,
> +#ifdef CONFIG_X86
> + .ex = (struct exception_table_entry *)__start___ex_table,
> + .ex_end = (struct exception_table_entry *)__stop___ex_table,
> +#endif
Is this together with ...
> +/*
> + * Becomes irrelevant when __init sections are cleared.
> + */
> +struct virtual_region kernel_inittext = {
> + .list = LIST_HEAD_INIT(kernel_inittext.list),
> + .skip = ignore_if_active,
> + .start = (unsigned long)_sinittext,
> + .end = (unsigned long)_einittext,
> +#ifdef CONFIG_X86
> + /* Even if they are __init their exception entry still gets stuck here. */
> + .ex = (struct exception_table_entry *)__start___ex_table,
> + .ex_end = (struct exception_table_entry *)__stop___ex_table,
> +#endif
... this really a good idea? I.e. are there not going to be any
odd side effects because of that redundancy?
Also note that the comment preceding this object is a single line one.
> +/*
> + * No locking. Additions are done either at startup (when there is only
> + * one CPU) or when all CPUs are running without IRQs.
> + *
> + * Deletions are big tricky. We MUST make sure all but one CPU
> + * are running cpu_relax().
> + *
> + */
> +LIST_HEAD(virtual_region_list);
I wonder whether this wouldn't better be static, with the iterator
that the various parties need getting put here as an out-of-line
function (instead of getting open coded in a couple of places).
> +void __init setup_virtual_regions(void)
> +{
> + ssize_t sz;
> + unsigned int i, idx;
> + static const struct bug_frame *const stop_frames[] = {
> + __start_bug_frames,
> + __stop_bug_frames_0,
> + __stop_bug_frames_1,
> + __stop_bug_frames_2,
> +#ifdef CONFIG_X86
> + __stop_bug_frames_3,
> +#endif
> + NULL
> + };
> +
> +#ifdef CONFIG_X86
> + sort_exception_tables();
> +#endif
> +
> + /* N.B. idx != i */
> + for ( idx = 0, i = 1; stop_frames[i]; i++, idx++ )
Irrespective of the comment - why two loop variables when they get
incremented in lockstep.
> + {
> + struct bug_frame *s;
> +
> + s = (struct bug_frame *)stop_frames[i-1];
Bogus cast, the more that it discards constness.
> @@ -95,10 +96,28 @@ static unsigned int get_symbol_offset(unsigned long pos)
> return name - symbols_names;
> }
>
> +bool_t __is_active_kernel_text(unsigned long addr, symbols_lookup_t *cb)
No new (and even more so global) symbols with double underscores
at their beginning please.
> @@ -108,13 +127,17 @@ const char *symbols_lookup(unsigned long addr,
> {
> unsigned long i, low, high, mid;
> unsigned long symbol_end = 0;
> + symbols_lookup_t symbol_lookup = NULL;
Pointless initializer.
> namebuf[KSYM_NAME_LEN] = 0;
> namebuf[0] = 0;
>
> - if (!is_active_kernel_text(addr))
> + if (!__is_active_kernel_text(addr, &symbol_lookup))
> return NULL;
>
> + if (symbol_lookup)
> + return (symbol_lookup)(addr, symbolsize, offset, namebuf);
Note that there are few coding style issues here (missing blanks,
superfluous parentheses).
> --- /dev/null
> +++ b/xen/include/xen/bug_ex_symbols.h
> @@ -0,0 +1,74 @@
> +/*
> + * Copyright (c) 2016 Oracle and/or its affiliates. All rights reserved.
> + *
> + */
> +
> +#ifndef __BUG_EX_SYMBOL_LIST__
> +#define __BUG_EX_SYMBOL_LIST__
> +
> +#include <xen/config.h>
> +#include <xen/list.h>
> +#include <xen/symbols.h>
> +
> +#ifdef CONFIG_X86
> +#include <asm/uaccess.h>
> +#endif
Why?
> +#include <asm/bug.h>
> +
> +struct virtual_region
> +{
> + struct list_head list;
> +
> +#define CHECKING_SYMBOL (1<<1)
> +#define CHECKING_BUG_FRAME (1<<2)
> +#define CHECKING_EXCEPTION (1<<3)
> + /*
> + * Whether to skip this region for particular searches. The flag
> + * can be CHECKING_[SYMBOL|BUG_FRAMES|EXCEPTION].
> + *
> + * If the function returns 1 this region will be skipped.
> + */
> + bool_t (*skip)(unsigned int flag, unsigned long priv);
> +
> + unsigned long start; /* Virtual address start. */
> + unsigned long end; /* Virtual address start. */
> +
> + /*
> + * If ->skip returns false for CHECKING_SYMBOL we will use
> + * 'symbols_lookup' callback to retrieve the name of the
> + * addr between start and end. If this is NULL the
> + * default lookup mechanism is used (the skip value is
> + * ignored).
> + */
> + symbols_lookup_t symbols_lookup;
> +
> + struct {
> + struct bug_frame *bugs; /* The pointer to array of bug frames. */
> + ssize_t n_bugs; /* The number of them. */
> + } frame[BUGFRAME_NR];
> +
> +#ifdef CONFIG_X86
> + struct exception_table_entry *ex;
> + struct exception_table_entry *ex_end;
> +#endif
The bug frame and exception related data are kind of odd to be
placed in a structure with this name. Would that not better be
accessed through ...
> + unsigned long priv; /* To be used by above funcionts if need to. */
... this by the interested parties?
Jan
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next prev parent reply other threads:[~2016-03-18 13:07 UTC|newest]
Thread overview: 124+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-15 17:56 [PATCH v4] xSplice v1 design and implementation Konrad Rzeszutek Wilk
2016-03-15 17:56 ` [PATCH v4 01/34] compat/x86: Remove unncessary #define Konrad Rzeszutek Wilk
2016-03-15 18:57 ` Andrew Cooper
2016-03-16 11:08 ` Jan Beulich
2016-03-17 0:44 ` Konrad Rzeszutek Wilk
2016-03-17 7:45 ` Jan Beulich
2016-03-15 17:56 ` [PATCH v4 02/34] libxc: Remove dead code (XENVER_capabilities) Konrad Rzeszutek Wilk
2016-03-15 18:04 ` Andrew Cooper
2016-03-15 18:08 ` Konrad Rzeszutek Wilk
2016-03-16 18:11 ` Wei Liu
2016-03-15 17:56 ` [PATCH v4 03/34] xsm/xen_version: Add XSM for the xen_version hypercall Konrad Rzeszutek Wilk
2016-03-18 11:55 ` Jan Beulich
2016-03-18 17:26 ` Konrad Rzeszutek Wilk
2016-03-21 11:22 ` Jan Beulich
2016-03-22 16:10 ` Konrad Rzeszutek Wilk
2016-03-22 17:54 ` Daniel De Graaf
2016-03-22 17:49 ` Daniel De Graaf
2016-03-24 15:34 ` anshul makkar
2016-03-24 19:19 ` Konrad Rzeszutek Wilk
2016-03-15 17:56 ` [PATCH v4 04/34] HYPERCALL_version_op. New hypercall mirroring XENVER_ but sane Konrad Rzeszutek Wilk
2016-03-15 18:29 ` Andrew Cooper
2016-03-15 20:19 ` Konrad Rzeszutek Wilk
2016-03-17 1:38 ` Konrad Rzeszutek Wilk
2016-03-17 14:28 ` Andrew Cooper
2016-03-18 12:36 ` Jan Beulich
2016-03-18 19:22 ` Konrad Rzeszutek Wilk
2016-03-21 12:45 ` Jan Beulich
2016-03-22 15:52 ` Konrad Rzeszutek Wilk
2016-03-22 16:06 ` Jan Beulich
2016-03-22 18:57 ` Konrad Rzeszutek Wilk
2016-03-22 19:28 ` Andrew Cooper
2016-03-22 20:39 ` Konrad Rzeszutek Wilk
2016-03-23 8:56 ` Jan Beulich
2016-03-24 2:37 ` Konrad Rzeszutek Wilk
2016-03-24 9:15 ` Jan Beulich
2016-03-24 11:39 ` Konrad Rzeszutek Wilk
2016-03-22 17:51 ` Daniel De Graaf
2016-03-15 17:56 ` [PATCH v4 05/34] libxc/libxl/python/xenstat: Use new XEN_VERSION_OP hypercall Konrad Rzeszutek Wilk
2016-03-15 18:45 ` Andrew Cooper
2016-03-16 12:31 ` George Dunlap
2016-03-16 18:11 ` Wei Liu
2016-03-17 1:08 ` Konrad Rzeszutek Wilk
2016-03-15 17:56 ` [PATCH v4 06/34] x86/arm: Add BUGFRAME_NR define and BUILD checks Konrad Rzeszutek Wilk
2016-03-15 18:54 ` Andrew Cooper
2016-03-16 11:49 ` Julien Grall
2016-03-18 12:40 ` Jan Beulich
2016-03-18 19:59 ` Konrad Rzeszutek Wilk
2016-03-21 12:49 ` Jan Beulich
2016-03-22 15:39 ` Konrad Rzeszutek Wilk
2016-03-22 15:58 ` Jan Beulich
2016-03-15 17:56 ` [PATCH v4 07/34] arm/x86: Use struct virtual_region to do bug, symbol, and (x86) exception tables Konrad Rzeszutek Wilk
2016-03-15 19:24 ` Andrew Cooper
2016-03-15 19:34 ` Konrad Rzeszutek Wilk
2016-03-15 19:51 ` Andrew Cooper
2016-03-15 20:02 ` Andrew Cooper
2016-03-16 10:33 ` Jan Beulich
2016-03-18 13:07 ` Jan Beulich [this message]
2016-03-22 20:18 ` Konrad Rzeszutek Wilk
2016-03-23 8:19 ` Jan Beulich
2016-03-23 11:17 ` Julien Grall
2016-03-23 11:21 ` Jan Beulich
2016-03-24 2:49 ` Konrad Rzeszutek Wilk
2016-03-24 9:20 ` Jan Beulich
2016-03-15 17:56 ` [PATCH v4 08/34] vmap: Make the while loop less fishy Konrad Rzeszutek Wilk
2016-03-15 19:33 ` Andrew Cooper
2016-03-17 11:49 ` Jan Beulich
2016-03-17 14:37 ` Andrew Cooper
2016-03-17 15:30 ` Jan Beulich
2016-03-17 16:06 ` Ian Jackson
2016-03-17 11:48 ` Jan Beulich
2016-03-17 16:08 ` Ian Jackson
2016-03-21 12:04 ` George Dunlap
2016-03-21 13:26 ` Jan Beulich
2016-03-21 14:22 ` George Dunlap
2016-03-21 15:05 ` Jan Beulich
2016-03-15 17:56 ` [PATCH v4 09/34] vmap: ASSERT on NULL Konrad Rzeszutek Wilk
2016-03-15 17:56 ` [PATCH v4 10/34] vmap: Add vmalloc_cb and vfree_cb Konrad Rzeszutek Wilk
2016-03-18 13:20 ` Jan Beulich
2016-03-15 17:56 ` [PATCH v4 11/34] xsplice: Design document Konrad Rzeszutek Wilk
2016-03-23 11:18 ` Jan Beulich
2016-03-23 20:12 ` Konrad Rzeszutek Wilk
2016-03-23 20:21 ` Konrad Rzeszutek Wilk
2016-03-24 3:15 ` Konrad Rzeszutek Wilk
2016-03-24 9:32 ` Jan Beulich
2016-03-15 17:56 ` [PATCH v4 12/34] xen/xsplice: Hypervisor implementation of XEN_XSPLICE_op Konrad Rzeszutek Wilk
2016-03-16 12:12 ` Julien Grall
2016-03-16 19:58 ` Konrad Rzeszutek Wilk
2016-03-23 13:51 ` Jan Beulich
2016-03-24 3:13 ` Konrad Rzeszutek Wilk
2016-03-24 9:29 ` Jan Beulich
2016-03-15 17:56 ` [PATCH v4 13/34] libxc: Implementation of XEN_XSPLICE_op in libxc Konrad Rzeszutek Wilk
2016-03-16 18:12 ` Wei Liu
2016-03-16 20:36 ` Konrad Rzeszutek Wilk
2016-03-15 17:56 ` [PATCH v4 14/34] xen-xsplice: Tool to manipulate xsplice payloads Konrad Rzeszutek Wilk
2016-03-16 18:12 ` Wei Liu
2016-03-15 17:56 ` [PATCH v4 15/34] xsplice: Add helper elf routines Konrad Rzeszutek Wilk
2016-03-15 17:56 ` [PATCH v4 16/34] xsplice: Implement payload loading Konrad Rzeszutek Wilk
2016-03-22 17:25 ` Konrad Rzeszutek Wilk
2016-03-15 17:56 ` [PATCH v4 17/34] xsplice: Implement support for applying/reverting/replacing patches Konrad Rzeszutek Wilk
2016-03-15 17:56 ` [PATCH v4 18/34] x86/xen_hello_world.xsplice: Test payload for patching 'xen_extra_version' Konrad Rzeszutek Wilk
2016-03-15 17:56 ` [PATCH v4 19/34] xsplice, symbols: Implement symbol name resolution on address Konrad Rzeszutek Wilk
2016-03-15 17:56 ` [PATCH v4 20/34] x86, xsplice: Print payload's symbol name and payload name in backtraces Konrad Rzeszutek Wilk
2016-03-15 17:56 ` [PATCH v4 21/34] xsplice: Add .xsplice.hooks functions and test-case Konrad Rzeszutek Wilk
2016-03-15 17:56 ` [PATCH v4 22/34] xsplice: Add support for bug frames Konrad Rzeszutek Wilk
2016-03-15 17:56 ` [PATCH v4 23/34] xsplice: Add support for exception tables Konrad Rzeszutek Wilk
2016-03-15 17:56 ` [PATCH v4 24/34] xsplice: Add support for alternatives Konrad Rzeszutek Wilk
2016-03-15 17:56 ` [PATCH v4 25/34] build_id: Provide ld-embedded build-ids Konrad Rzeszutek Wilk
2016-03-16 18:34 ` Julien Grall
2016-03-16 21:02 ` Konrad Rzeszutek Wilk
2016-03-17 1:12 ` Konrad Rzeszutek Wilk
2016-03-17 11:08 ` Julien Grall
2016-03-17 13:39 ` Konrad Rzeszutek Wilk
2016-03-15 17:56 ` [PATCH v4 26/34] HYPERCALL_version_op: Add VERSION_OP_build_id to retrieve build-id Konrad Rzeszutek Wilk
2016-03-15 17:56 ` [PATCH v4 27/34] libxl: info: Display build_id of the hypervisor using XEN_VERSION_OP_build_id Konrad Rzeszutek Wilk
2016-03-16 18:12 ` Wei Liu
2016-03-15 17:56 ` [PATCH v4 28/34] xsplice: Print build_id in keyhandler and on bootup Konrad Rzeszutek Wilk
2016-03-15 17:56 ` [PATCH v4 29/34] xsplice: Stacking build-id dependency checking Konrad Rzeszutek Wilk
2016-03-15 17:56 ` [PATCH v4 30/34] xsplice/xen_replace_world: Test-case for XSPLICE_ACTION_REPLACE Konrad Rzeszutek Wilk
2016-03-15 17:56 ` [PATCH v4 31/34] xsplice: Print dependency and payloads build_id in the keyhandler Konrad Rzeszutek Wilk
2016-03-15 17:56 ` [PATCH v4 32/34] xsplice: Prevent duplicate payloads from being loaded Konrad Rzeszutek Wilk
2016-03-15 17:56 ` [PATCH v4 33/34] xsplice: Add support for shadow variables Konrad Rzeszutek Wilk
2016-03-15 17:56 ` [PATCH v4 34/34] MAINTAINERS/xsplice: Add myself and Ross as the maintainers Konrad Rzeszutek Wilk
2016-03-16 11:10 ` Jan Beulich
2016-03-17 0:44 ` Konrad Rzeszutek Wilk
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