Changeset b808660 in mainline


Ignore:
Timestamp:
2010-07-08T20:03:52Z (14 years ago)
Author:
Jakub Jermar <jakub@…>
Branches:
lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export
Children:
bee2d4c
Parents:
9097982f
Message:

Do not align ia32 int handlers on any pre-defined power-of-two boundary but
rather define each one as a separate procedure with its own global label. The
label is used to populate the IDT and it also helps to maintain consistency
between C and assembly.

The old way was very error-prone because one did not get a warning when a
handler exceeded the size limit given by the alignment, which usually resulted
in very weird crashes.

In principle, the old way was also rather wasteful as the handler had to be
aligned on a power-of-two address. With the int handler size around 160 bytes,
the bytes 160 - 255 in each handler were simply wasted. In practice, however,
the image.iso size did not change (I'd expect it to drop by around 8K).

The old way did not detect a mistmatch between the C code idea of how many IDT
entries there are and the assembly language code idea of the same thing. It was
possible to initialize an IDT entry to point to some garbage and nobody would
notice until the int occurred.

The new method was a bit tiresome to write as there was a lot of copy'n'paste.
But since it was a one-time effort, I lumped it. If you know of a way to write a
for-loop in C preprocessor or use GAS assmebler macros in a sensible way, I will
gladly use your improvement.

Location:
kernel/arch/ia32
Files:
3 edited

Legend:

Unmodified
Added
Removed

  • kernel/arch/ia32/include/asm.h

    r9097982f rb808660  
    425425
    426426extern void paging_on(void);
    427 extern void interrupt_handlers(void);
    428427extern void enable_l_apic_in_msr(void);
    429428
    … …  
    431430extern void asm_fake_loop(uint32_t);
    432431
     432extern uintptr_t int_0;
     433extern uintptr_t int_1;
     434extern uintptr_t int_2;
     435extern uintptr_t int_3;
     436extern uintptr_t int_4;
     437extern uintptr_t int_5;
     438extern uintptr_t int_6;
     439extern uintptr_t int_7;
     440extern uintptr_t int_8;
     441extern uintptr_t int_9;
     442extern uintptr_t int_10;
     443extern uintptr_t int_11;
     444extern uintptr_t int_12;
     445extern uintptr_t int_13;
     446extern uintptr_t int_14;
     447extern uintptr_t int_15;
     448extern uintptr_t int_16;
     449extern uintptr_t int_17;
     450extern uintptr_t int_18;
     451extern uintptr_t int_19;
     452extern uintptr_t int_20;
     453extern uintptr_t int_21;
     454extern uintptr_t int_22;
     455extern uintptr_t int_23;
     456extern uintptr_t int_24;
     457extern uintptr_t int_25;
     458extern uintptr_t int_26;
     459extern uintptr_t int_27;
     460extern uintptr_t int_28;
     461extern uintptr_t int_29;
     462extern uintptr_t int_30;
     463extern uintptr_t int_31;
     464extern uintptr_t int_32;
     465extern uintptr_t int_33;
     466extern uintptr_t int_34;
     467extern uintptr_t int_35;
     468extern uintptr_t int_36;
     469extern uintptr_t int_37;
     470extern uintptr_t int_38;
     471extern uintptr_t int_39;
     472extern uintptr_t int_40;
     473extern uintptr_t int_41;
     474extern uintptr_t int_42;
     475extern uintptr_t int_43;
     476extern uintptr_t int_44;
     477extern uintptr_t int_45;
     478extern uintptr_t int_46;
     479extern uintptr_t int_47;
     480extern uintptr_t int_48;
     481extern uintptr_t int_49;
     482extern uintptr_t int_50;
     483extern uintptr_t int_51;
     484extern uintptr_t int_52;
     485extern uintptr_t int_53;
     486extern uintptr_t int_54;
     487extern uintptr_t int_55;
     488extern uintptr_t int_56;
     489extern uintptr_t int_57;
     490extern uintptr_t int_58;
     491extern uintptr_t int_59;
     492extern uintptr_t int_60;
     493extern uintptr_t int_61;
     494extern uintptr_t int_62;
     495extern uintptr_t int_63;
     496
    433497#endif
    434498

  • kernel/arch/ia32/src/asm.S

    r9097982f rb808660  
    4444.global paging_on
    4545.global enable_l_apic_in_msr
    46 .global interrupt_handlers
    4746.global memsetb
    4847.global memsetw
    … …  
    273272 *
    274273 */
    275 #define INTERRUPT_ALIGN  256
    276 
    277 .macro handler i n
     274
     275.macro handler i
     276.global int_\i
     277int_\i:
    278278        .ifeq \i - 0x30
    279279                /* Syscall handler */
    … …  
    472472               
    473473        .endif
    474        
    475         .align INTERRUPT_ALIGN
    476         .if (\n - \i) - 1
    477                 handler "(\i + 1)", \n
    478         .endif
    479474.endm
    480475
    481 /* Keep in sync with pm.h! */
    482 #define IDT_ITEMS  64
    483 
    484 .align INTERRUPT_ALIGN
     476#define LIST_0_63 \
     477        0, 1, 2, 3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,\
     478        28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,\
     479        53,54,55,56,57,58,59,60,61,62,63
     480
    485481interrupt_handlers:
    486         h_start:
    487                 handler 0 IDT_ITEMS
    488         h_end:
     482.irp cnt, LIST_0_63
     483        handler \cnt
     484.endr
    489485
    490486/** Print Unicode character to EGA display.
    … …  
    635631        ret
    636632
    637 .data
    638 .global interrupt_handler_size
    639 
    640 interrupt_handler_size: .long (h_end - h_start) / IDT_ITEMS

  • kernel/arch/ia32/src/pm.c

    r9097982f rb808660  
    139139                        d->access |= DPL_USER;
    140140                }
    141                
    142                 idt_setoffset(d, ((uintptr_t) interrupt_handlers) +
    143                     i * interrupt_handler_size);
    144141        }
    145 }
    146 
     142
     143        d = &idt[0];
     144        idt_setoffset(d++, (uintptr_t) &int_0);
     145        idt_setoffset(d++, (uintptr_t) &int_1);
     146        idt_setoffset(d++, (uintptr_t) &int_2);
     147        idt_setoffset(d++, (uintptr_t) &int_3);
     148        idt_setoffset(d++, (uintptr_t) &int_4);
     149        idt_setoffset(d++, (uintptr_t) &int_5);
     150        idt_setoffset(d++, (uintptr_t) &int_6);
     151        idt_setoffset(d++, (uintptr_t) &int_7);
     152        idt_setoffset(d++, (uintptr_t) &int_8);
     153        idt_setoffset(d++, (uintptr_t) &int_9);
     154        idt_setoffset(d++, (uintptr_t) &int_10);
     155        idt_setoffset(d++, (uintptr_t) &int_11);
     156        idt_setoffset(d++, (uintptr_t) &int_12);
     157        idt_setoffset(d++, (uintptr_t) &int_13);
     158        idt_setoffset(d++, (uintptr_t) &int_14);
     159        idt_setoffset(d++, (uintptr_t) &int_15);
     160        idt_setoffset(d++, (uintptr_t) &int_16);
     161        idt_setoffset(d++, (uintptr_t) &int_17);
     162        idt_setoffset(d++, (uintptr_t) &int_18);
     163        idt_setoffset(d++, (uintptr_t) &int_19);
     164        idt_setoffset(d++, (uintptr_t) &int_20);
     165        idt_setoffset(d++, (uintptr_t) &int_21);
     166        idt_setoffset(d++, (uintptr_t) &int_22);
     167        idt_setoffset(d++, (uintptr_t) &int_23);
     168        idt_setoffset(d++, (uintptr_t) &int_24);
     169        idt_setoffset(d++, (uintptr_t) &int_25);
     170        idt_setoffset(d++, (uintptr_t) &int_26);
     171        idt_setoffset(d++, (uintptr_t) &int_27);
     172        idt_setoffset(d++, (uintptr_t) &int_28);
     173        idt_setoffset(d++, (uintptr_t) &int_29);
     174        idt_setoffset(d++, (uintptr_t) &int_30);
     175        idt_setoffset(d++, (uintptr_t) &int_31);
     176        idt_setoffset(d++, (uintptr_t) &int_32);
     177        idt_setoffset(d++, (uintptr_t) &int_33);
     178        idt_setoffset(d++, (uintptr_t) &int_34);
     179        idt_setoffset(d++, (uintptr_t) &int_35);
     180        idt_setoffset(d++, (uintptr_t) &int_36);
     181        idt_setoffset(d++, (uintptr_t) &int_37);
     182        idt_setoffset(d++, (uintptr_t) &int_38);
     183        idt_setoffset(d++, (uintptr_t) &int_39);
     184        idt_setoffset(d++, (uintptr_t) &int_40);
     185        idt_setoffset(d++, (uintptr_t) &int_41);
     186        idt_setoffset(d++, (uintptr_t) &int_42);
     187        idt_setoffset(d++, (uintptr_t) &int_43);
     188        idt_setoffset(d++, (uintptr_t) &int_44);
     189        idt_setoffset(d++, (uintptr_t) &int_45);
     190        idt_setoffset(d++, (uintptr_t) &int_46);
     191        idt_setoffset(d++, (uintptr_t) &int_47);
     192        idt_setoffset(d++, (uintptr_t) &int_48);
     193        idt_setoffset(d++, (uintptr_t) &int_49);
     194        idt_setoffset(d++, (uintptr_t) &int_50);
     195        idt_setoffset(d++, (uintptr_t) &int_51);
     196        idt_setoffset(d++, (uintptr_t) &int_52);
     197        idt_setoffset(d++, (uintptr_t) &int_53);
     198        idt_setoffset(d++, (uintptr_t) &int_54);
     199        idt_setoffset(d++, (uintptr_t) &int_55);
     200        idt_setoffset(d++, (uintptr_t) &int_56);
     201        idt_setoffset(d++, (uintptr_t) &int_57);
     202        idt_setoffset(d++, (uintptr_t) &int_58);
     203        idt_setoffset(d++, (uintptr_t) &int_59);
     204        idt_setoffset(d++, (uintptr_t) &int_60);
     205        idt_setoffset(d++, (uintptr_t) &int_61);
     206        idt_setoffset(d++, (uintptr_t) &int_62);
     207        idt_setoffset(d++, (uintptr_t) &int_63);
     208}
    147209
    148210/* Clean IOPL(12,13) and NT(14) flags in EFLAGS register */
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