#ifndef _DWARF_AUX_H #define _DWARF_AUX_H /* * dwarf-aux.h : libdw auxiliary interfaces * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. * */ #include #include #include #include /* Find the realpath of the target file */ const char *cu_find_realpath(Dwarf_Die *cu_die, const char *fname); /* Get DW_AT_comp_dir (should be NULL with older gcc) */ const char *cu_get_comp_dir(Dwarf_Die *cu_die); /* Get a line number and file name for given address */ int cu_find_lineinfo(Dwarf_Die *cudie, unsigned long addr, const char **fname, int *lineno); /* Walk on funcitons at given address */ int cu_walk_functions_at(Dwarf_Die *cu_die, Dwarf_Addr addr, int (*callback)(Dwarf_Die *, void *), void *data); /* Get DW_AT_linkage_name (should be NULL for C binary) */ const char *die_get_linkage_name(Dwarf_Die *dw_die); /* Ensure that this DIE is a subprogram and definition (not declaration) */ bool die_is_func_def(Dwarf_Die *dw_die); /* Ensure that this DIE is an instance of a subprogram */ bool die_is_func_instance(Dwarf_Die *dw_die); /* Compare diename and tname */ bool die_compare_name(Dwarf_Die *dw_die, const char *tname); /* Matching diename with glob pattern */ bool die_match_name(Dwarf_Die *dw_die, const char *glob); /* Get callsite line number of inline-function instance */ int die_get_call_lineno(Dwarf_Die *in_die); /* Get callsite file name of inlined function instance */ const char *die_get_call_file(Dwarf_Die *in_die); /* Get type die */ Dwarf_Die *die_get_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem); /* Get a type die, but skip qualifiers and typedef */ Dwarf_Die *die_get_real_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem); /* Check whether the DIE is signed or not */ bool die_is_signed_type(Dwarf_Die *tp_die); /* Get data_member_location offset */ int die_get_data_member_location(Dwarf_Die *mb_die, Dwarf_Word *offs); /* Return values for die_find_child() callbacks */ enum { DIE_FIND_CB_END = 0, /* End of Search */ DIE_FIND_CB_CHILD = 1, /* Search only children */ DIE_FIND_CB_SIBLING = 2, /* Search only siblings */ DIE_FIND_CB_CONTINUE = 3, /* Search children and siblings */ }; /* Search child DIEs */ Dwarf_Die *die_find_child(Dwarf_Die *rt_die, int (*callback)(Dwarf_Die *, void *), void *data, Dwarf_Die *die_mem); /* Search a non-inlined function including given address */ Dwarf_Die *die_find_realfunc(Dwarf_Die *cu_die, Dwarf_Addr addr, Dwarf_Die *die_mem); /* Search a non-inlined function with tail call at given address */ Dwarf_Die *die_find_tailfunc(Dwarf_Die *cu_die, Dwarf_Addr addr, Dwarf_Die *die_mem); /* Search the top inlined function including given address */ Dwarf_Die *die_find_top_inlinefunc(Dwarf_Die *sp_die, Dwarf_Addr addr, Dwarf_Die *die_mem); /* Search the deepest inlined function including given address */ Dwarf_Die *die_find_inlinefunc(Dwarf_Die *sp_die, Dwarf_Addr addr, Dwarf_Die *die_mem); /* Walk on the instances of given DIE */ int die_walk_instances(Dwarf_Die *in_die, int (*callback)(Dwarf_Die *, void *), void *data); /* Walker on lines (Note: line number will not be sorted) */ typedef int (* line_walk_callback_t) (const char *fname, int lineno, Dwarf_Addr addr, void *data); /* * Walk on lines inside given DIE. If the DIE is a subprogram, walk only on * the lines inside the subprogram, otherwise the DIE must be a CU DIE. */ int die_walk_lines(Dwarf_Die *rt_die, line_walk_callback_t callback, void *data); /* Find a variable called 'name' at given address */ Dwarf_Die *die_find_variable_at(Dwarf_Die *sp_die, const char *name, Dwarf_Addr addr, Dwarf_Die *die_mem); /* Find a member called 'name' */ Dwarf_Die *die_find_member(Dwarf_Die *st_die, const char *name, Dwarf_Die *die_mem); /* Get the name of given variable DIE */ int die_get_typename(Dwarf_Die *vr_die, struct strbuf *buf); /* Get the name and type of given variable DIE, stored as "type\tname" */ int die_get_varname(Dwarf_Die *vr_die, struct strbuf *buf); int die_get_var_range(Dwarf_Die *sp_die, Dwarf_Die *vr_die, struct strbuf *buf); /* Check if target program is compiled with optimization */ bool die_is_optimized_target(Dwarf_Die *cu_die); /* Use next address after prologue as probe location */ void die_skip_prologue(Dwarf_Die *sp_die, Dwarf_Die *cu_die, Dwarf_Addr *entrypc); #endif span='2' class='oid'>5e95c29eb7a49a5c026e8f4af0c6b9da46f52122 /drivers/usb/phy parentf466ae66fa6a599f9a53b5f9bafea4b8cfffa7fb (diff)
rcu: Narrow early boot window of illegal synchronous grace periods
The current preemptible RCU implementation goes through three phases during bootup. In the first phase, there is only one CPU that is running with preemption disabled, so that a no-op is a synchronous grace period. In the second mid-boot phase, the scheduler is running, but RCU has not yet gotten its kthreads spawned (and, for expedited grace periods, workqueues are not yet running. During this time, any attempt to do a synchronous grace period will hang the system (or complain bitterly, depending). In the third and final phase, RCU is fully operational and everything works normally. This has been OK for some time, but there has recently been some synchronous grace periods showing up during the second mid-boot phase. This code worked "by accident" for awhile, but started failing as soon as expedited RCU grace periods switched over to workqueues in commit 8b355e3bc140 ("rcu: Drive expedited grace periods from workqueue"). Note that the code was buggy even before this commit, as it was subject to failure on real-time systems that forced all expedited grace periods to run as normal grace periods (for example, using the rcu_normal ksysfs parameter). The callchain from the failure case is as follows: early_amd_iommu_init() |-> acpi_put_table(ivrs_base); |-> acpi_tb_put_table(table_desc); |-> acpi_tb_invalidate_table(table_desc); |-> acpi_tb_release_table(...) |-> acpi_os_unmap_memory |-> acpi_os_unmap_iomem |-> acpi_os_map_cleanup |-> synchronize_rcu_expedited The kernel showing this callchain was built with CONFIG_PREEMPT_RCU=y, which caused the code to try using workqueues before they were initialized, which did not go well. This commit therefore reworks RCU to permit synchronous grace periods to proceed during this mid-boot phase. This commit is therefore a fix to a regression introduced in v4.9, and is therefore being put forward post-merge-window in v4.10. This commit sets a flag from the existing rcu_scheduler_starting() function which causes all synchronous grace periods to take the expedited path. The expedited path now checks this flag, using the requesting task to drive the expedited grace period forward during the mid-boot phase. Finally, this flag is updated by a core_initcall() function named rcu_exp_runtime_mode(), which causes the runtime codepaths to be used. Note that this arrangement assumes that tasks are not sent POSIX signals (or anything similar) from the time that the first task is spawned through core_initcall() time. Fixes: 8b355e3bc140 ("rcu: Drive expedited grace periods from workqueue") Reported-by: "Zheng, Lv" <lv.zheng@intel.com> Reported-by: Borislav Petkov <bp@alien8.de> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Tested-by: Stan Kain <stan.kain@gmail.com> Tested-by: Ivan <waffolz@hotmail.com> Tested-by: Emanuel Castelo <emanuel.castelo@gmail.com> Tested-by: Bruno Pesavento <bpesavento@infinito.it> Tested-by: Borislav Petkov <bp@suse.de> Tested-by: Frederic Bezies <fredbezies@gmail.com> Cc: <stable@vger.kernel.org> # 4.9.0-
Diffstat (limited to 'drivers/usb/phy')